Childhood Acute Lymphoblastic Leukemia Research Articles

Case report: Pediatric acute lymphoblastic leukemia with trisomy 5 as sole cytogenetic abnormality

Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood and represents about 75 -80% of ALL in pediatric age group. ALL is characterised by uncontrolled proliferation of abnormal, immature lymphocytes and their progenitors and replacing the bone marrow elements and other lymphoid organs by leukemic cells (ALL blasts). The 5 year survival rate for childhood ALL is about 90% overall, children in lower risk groups have a better prognosis than those in higher risk group. Risk assessment is mainly based on cytogenetic and molecular factors in addition, clinical symptoms and signs, White blood cell count at diagnosis are all recognized for stratification. In present case the cytogenetic analysis showed the presence of trisomy 5 as a sole numerical abnormality. Trisomy 5 accounts for aneuploidy change in the cytogenetic analysis. The gain or loss of whole chromosome, ie aneuploidy is a major genomic insult in human cancers. Aneuploidy is observed in ~90% of solid tumors and~60% of hematological maignancies. The increased gene expression in trisomy 5 causes chromosomal instability (CIN), microsatellite instability (MIN) and genomic instabilty which inturn causes the cancer genome to undergo evolution, adaptation and favors tumor progression in patients with B cell acute lymphoblastic leukemia.

Maternal serum concentrations of per- and polyfluoroalkyl substances and childhood acute lymphoblastic leukemia.

Per- and polyfluoroalkyl substances (PFAS) are widespread and environmentally persistent chemicals with immunotoxic properties. Children are prenatally exposed through maternal transfer of PFAS to cord blood, but no studies have investigated the relationship with childhood leukemia. We measured maternal serum levels of 19 PFAS in first-trimester samples collected in 1986-2010 and evaluated associations with acute lymphoblastic leukemia in full-term offspring (aged younger than 15 years) for 400 cases and 400 controls in the Finnish Maternity Cohort, matched on sample year, mother's age, gestational age, birth order, and child's sex. We analyzed continuous and categorical exposures, estimating odds ratios (ORs) and 95% confidence intervals (CIs) via conditional logistic regression adjusted for maternal smoking and correlated PFAS (ρ ≥ ±0.3). We also stratified by calendar period, mean diagnosis age, and the child's sex. N-methyl-perfluorooctane sulfonamidoacetic acid was associated with acute lymphoblastic leukemia in continuous models (per each doubling in levels: ORperlog2 = 1.22, 95% CI = 1.07 to 1.39), with a positive exposure-response across categories (OR>90th percentile = 2.52, 95% CI = 1.33 to 4.78; Ptrend = .01). Although we found no relationship with perfluorooctane sulfonic acid overall, an association was observed in samples collected in 1986-1995, when levels were highest (median = 17.9 µg/L; ORperlog2 = 4.01, 95% CI = 1.62 to 9.93). A positive association with perfluorononanoic acid was suggested among first births (Pinteraction = .06). The N-methyl-perfluorooctane sulfonamidoacetic acid association was mainly limited to children diagnosed before age 5 years (Pinteraction = .02). We found no consistent patterns of association with other PFAS or differences by sex. These novel data offer evidence of a relationship between some PFAS and risk of the most common childhood cancer worldwide, including associations with the highest levels of perfluorooctanesulfonic acid and with a precursor, N-methyl-perfluorooctane sulfonamidoacetic acid.

T(1;4) translocation in a child with acute lymphoblastic leukemia: a case report

BackgroundAcute lymphoblastic leukemia is the most common childhood cancer, with an 80% frequency in children between 1 and 10 years old. The outcome and prognosis of acute lymphoblastic leukemia in children depends on various factors, such as age, clinical and biological features, and cytogenetic factors.Case presentationWe report the case of a pediatric patient, a 4-year-old Moroccan female who was referred to the Hematology and Oncology Department of 20 August 1953 Hospital in Casablanca and diagnosed with B-cell acute lymphoblastic leukemia associated with a rare genetic chromosomal abnormality.ConclusionTranslocation (1;4)(p21;p15) is a relatively rare chromosomal abnormality found in human leukemia and was never described isolated in pediatric B-cell acute lymphoblastic leukemia patients. It showed a good evolution by complete remission and recovery of this patient after receiving all chemotherapy and after 8 years of follow-up.

Micafungin twice-a-week for prophylaxis of invasive Aspergillus infections in children with acute lymphoblastic leukaemia: A controlled cohort study

ObjectivesInvasive Aspergillus infections during the early phase of childhood acute lymphoblastic leukemia (ALL) treatment come with morbidity and mortality. The interaction with vincristine hampers first-line azole prophylaxis. We describe the efficacy of an alternative twice-a-week micafungin regimen for Aspergillus prophylaxis. MethodsNewly diagnosed paediatric patients with ALL treated according to the ALL-11 protocol received micafungin twice-a-week (9 mg/kg/dose [max. 300 mg]) during the induction course (first 35 days of treatment) as part of routine care. A historical control cohort without Aspergillus prophylaxis was used. During the first consolidation course (day 36-79), standard itraconazole prophylaxis was used in both groups.The percentage of proven/probable Aspergillus infections during the induction/first consolidation course was compared between the cohorts. The cumulative incidence of proven/probable Aspergillus infections was estimated using a competing risk model. For safety evaluation, liver laboratory chemistry values were analysed. ResultsA total of 169 and 643 paediatric patients with ALL were treated in the micafungin cohort (median age: 4 years [range 1-17]) and historical cohort (median age: 5 years [range 1-17]). The percentage of proven/probable Aspergillus infections was 1·2% (2/169) in the micafungin cohort versus 5·8% (37/643) in the historical cohort (p=0.013; Fisher's exact test). The differences in estimated cumulative incidence were assessed (p=0·014; Gray's test). Although significantly higher ALT/AST values were reported in the micafungin cohort, no clinically relevant side effects were observed. ConclusionsTwice-a-week micafungin prophylaxis during the induction course significantly reduced the occurrence of proven/probable Aspergillus infections in the early phase of childhood ALL treatment.

Characterisation of FLT3 alterations in childhood acute lymphoblastic leukaemia

BackgroundAlterations of FLT3 are among the most common driver events in acute leukaemia with important clinical implications, since it allows patient classification into prognostic groups and the possibility of personalising therapy thanks to the availability of FLT3 inhibitors. Most of the knowledge on FLT3 implications comes from the study of acute myeloid leukaemia and so far, few studies have been performed in other leukaemias.MethodsA comprehensive genomic (DNA-seq in 267 patients) and transcriptomic (RNA-seq in 160 patients) analysis of FLT3 in 342 childhood acute lymphoblastic leukaemia (ALL) patients was performed. Mutations were functionally characterised by in vitro experiments.ResultsPoint mutations (PM) and internal tandem duplications (ITD) were detected in 4.3% and 2.7% of the patients, respectively. A new activating mutation of the TKD, G846D, conferred oncogenic properties and sorafenib resistance. Moreover, a novel alteration involving the circularisation of read-through transcripts (rt-circRNAs) was observed in 10% of the cases. Patients presenting FLT3 alterations exhibited higher levels of the receptor. In addition, patients with ZNF384- and MLL/KMT2A-rearranged ALL, as well as hyperdiploid subtype, overexpressed FLT3.DiscussionOur results suggest that specific ALL subgroups may also benefit from a deeper understanding of the biology of FLT3 alterations and their clinical implications.

A Review of Acute Lymphocytic Leukemia (ALL) in the Pediatric Population: Evaluating Current Trends and Changes in Guidelines in the Past Decade.

Acute lymphocytic leukemia (ALL) is a commonly diagnosed cancer in children.Despite technological advancements to improvetreatment and survival rates, there has been a steady increase in the incidence of ALL and treatment failures. This paper discusses the pathogenic interaction between genetic and environmental factors leading to childhood ALL. It evaluates the current treatment guidelines and notable obstacles leading to resistance, relapse, and treatment toxicities. The reviewevaluates a 10-year trend in the management guidelines of pediatric ALL through asystematic literature review of recordsfrom 2012 to 2023. Findings show that improvement in the five-year survival rates, notwithstandingrates of relapse and incurable diseases, is still high. Furthermore, several risk factors, including an interplay between genetic and environmental factors, are largely contributory to the outcome of ALL treatments and its overall incidence. Moreover, huge financial costs have remained a significant challengein outcomes. There remains a need to provide individualized treatment plans, shared decision-making, and goals of care as parts of the management guidelines for the best possible outcomes. We expect that future advancements will increase overall survival rates and disease-free years.

The association of environmental factors with neurocognitive outcomes in survivors of childhood acute lymphoblastic leukemia (ALL).

To investigate the association of environmental factors, rehabilitation services during therapy and socioeconomic status (SES - insurance type), with neurocognitive outcomes at the end of therapy for survivors of childhood acute lymphoblastic leukemia (ALL). Survivors (n = 236) treated on the St. Jude Total Therapy Study 16 completed end of therapy testing with performance measures (IQ, attention, processing speed, fine motor skills, academics) and caregiver ratings (attention, executive function, adaptive skills). Environmental factors were abstracted from the medical record. Distribution of sex (47.3% female, p = 0.399), treatment arm (45.5% low risk, 54.5% standard/high risk p = 0.929), insurance type (47.7% private, 52.3% public/none, p = 0.117), and mean age at diagnosis (7.7 vs. 6.8years, p = 0.143) were similar for groups with (n = 110; 46.6%) and without (n = 126; 53.6%) rehabilitation services during therapy. Compared to those without rehabilitation, the rehabilitation group (n = 110; 46.4%) had more caregiver reported problems with attention (Z = -0.28 vs. 0.43, p = 0.022), executive function (Z = -0.50 vs. -0.08, p = 0.003), and adaptive skills (Z = -0.41 vs.-0.13, p = 0.031). Among the rehabilitation group, there was no difference in outcomes by insurance status. Among those without rehabilitation, those with public insurance had worse neurocognitive outcomes than those with private insurance in IQ (Z = -0.04 vs. -0.45, p = 0.0115), processing speed (Z = -0.10 vs. -0.75, p = 0.0030), reading (Z = 0.18 vs. -0.59, p < 0.0001), and math (Z = -0.04 vs. -0.50, p = 0.0021). Participation in rehabilitation services during early intensive therapy is associated with end of therapy caregiver-reported neurocognitive outcomes in daily life.

Time of Attainment of Clinical Remission and Peripheral Blood Count Recovery during Induction Chemotherapy for Childhood Acute Lymphoblastic Leukemia

Background: Acute lymphoblastic leukemia(ALL) is the most common pediatric malignancy. Infection and bleeding are the leading cause of death during induction chemotherapy in childhood ALL. So, proper knowledge about anticipated infection and bleeding are very important during this period. But the duration of clinical remission and recovery of peripheral blood count during induction chemotherapy is not well reported in literature. Objective: The aim of the study was to determine the time of attainment of clinical remission and recovery of peripheral blood count after initiation of induction chemotherapy and to determine if the duration of clinical remission and peripheral blood count recovery differs between therapeutic risk groups. Methods: This prospective observational study was conducted from January 2021 to December 2021 in the Department of Paediatric Haematology and Oncology, BSMMU. Newly diagnosed admitted Eighty-Six ALL of both sexes aged 1 to 17.9 years were included. After commencing chemotherapy, physical examination was recorded every day until clinical remission and complete blood count (CBC) was recorded one to two days interval until peripheral blood count recovery. The number of packed red blood cell (PRBC) and platelet transfusions and the number of days of intravenous antibiotics were recorded. Results: Mean duration of clinical remission, complete Hemoglobin (Hb), Absolute neutrophil count(ANC) and platelet recovery was 8.4 ± 4.5 days, 25±7.9 days, 23.3±5.6 days and 21.8±6.4 days respectively (p&lt;0.01). Time to attain partial recovery of platelet was 14.0±4.9 days in high risk and 19.2±5.3 days in standard risk group. PRBC transfusion requirement was 2.2±1.2 units in high risk group and 1.7±0.8 units in standard risk group (p&lt;0.05). Time to attain partial recovery of ANC, number of days with I/V antibiotics and duration of treatment interruption were higher in high risk group. Conclusion: Time of clinical remission was similar between risk group. Platelet recovery occurred earlier than Hemoglobin (Hb) and absolute neutrophil count (ANC) recovery. Transfusion and supportive care requirement were more in high risk group during induction chemotherapy. So, more supportive care should be arranged up to three weeks of induction period to increase survival of high risk childhood ALL. Bangladesh Med Res Counc Bull 2023; 49: 177-182

Echocardiographic Parameters Associated With Cardiorespiratory Fitness and Physical Activity in Childhood Acute Lymphoblastic Leukemia Survivors.

Children's exposure to chemotherapeutic agents causes several long-term adverse effects but physical activity has been evidenced to be an effective strategy to improve cardiac function. This cross-sectional study aimed to explore the association between physical activity levels, cardiorespiratory fitness, and cardiac parameters measured by echocardiography. Participants were 216n childhood acute lymphoblastic leukemia survivors who underwent a maximal cardiopulmonary exercise test and self-reported their daily minutes of moderate to vigorous physical activity. They underwent a complete transthoracic echocardiographic assessment. Systolic and diastolic function analysis and strain images analysis were performed. The associations were studied through the preventive fraction (examined with univariate crude and adjusted logistic regression models) of regular physical activity (≥150min·wk-1) and adequate cardiorespiratory fitness levels (above the median ≥ 32.0mL·kg-1·min-1) on cardiac parameters. Crude analysis shows that regular physical activity was associated with a significant preventive fraction in mitral E/A ratio (56%; P = .013), while adjusted analyses highlighted a nonsignificant reduction of 74% to 37% in the prevalence of cardiac parameters associated with physical activity. Similar associations of adequate cardiorespiratory fitness on cardiac parameters were observed. Adjusted analyses revealed a nonsignificant reduction of 7% to 86% in the prevalence of cardiac parameters associated with cardiorespiratory fitness. This study reports that regular physical activity and adequate cardiorespiratory fitness were associated with a higher preventive fraction. Thus, engaging in physical activity prevents childhood acute lymphoblastic leukemia survivors' cardiac dysfunctions. These findings are novel and clinically relevant in pediatric cardiooncology and provide additional evidence to strengthen the benefits of exercise as long-term care in childhood cancer survivors.

Interleukin-8 Rs4073 Genotypes as Prognostic Predictors for Childhood Acute Lymphocytic Leukemia.

Interleukin 8 (IL-8) is highly expressed in refractory acute lymphocytic leukemia (ALL) cells. This study aimed to investigate the contribution of IL-8 polymorphisms to the risk of childhood ALL. The genotypes of IL-8 rs4073, rs2227306, rs2227543, and rs1126647 were determined in 266 childhood ALL cases and 266 controls using the PCR-RFLP method. Additionally, we assessed whether the interactions of these genotypes with age and sex contributed to childhood ALL risk. The distributions of genotypic and allelic frequencies of IL-8 rs4073, rs2227306, rs2227543, and rs1126647 were not significantly different between childhood ALL cases and controls (all p>0.05). However, carriers of the variant AA genotype at IL-8 rs4073 had a significantly higher risk of childhood ALL among those aged ≤3.5 years and among girls (OR=2.39 and 3.32, 95%CI=1.21-4.73 and 1.51-7.30, p=0.0182 and 0.0042, respectively). In the stratification analysis, IL-8 rs4073 AT and AA genotypes were associated with higher childhood ALL risk classification and shorter survival time (OR=2.21 and 4.13, 95%CI=1.29-3.78 and 1.87-9.10, p=0.0054 and 0.0002, respectively). There was no positive association for rs2227306, rs2227543, or rs1126647 (all p>0.05). The A allele of IL-8 rs4073 can serve as a diagnostic predictor for childhood ALL, but only in girls and patients younger than or equal to 3.5 years old. More importantly, it can serve as a prognostic marker for high-risk classification and shorter survival time. Further validation studies can help extend the use of this prognostic predictor in clinical practice.

IKZF3 polymorphisms contribute to the increased risk of acute lymphoblastic leukemia in children.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. IKZF3 (IKAROS family zinc finger 3) is a hematopoietic-specific transcription factor, and it has been validated that it is involved in leukemia. However, the role of IKZF3 single-nucleotide polymorphisms (SNPs) remains unclear. In this case-control study, the authors investigated the association of IKZF3 SNPs with ALL in children. Six IKZF3 reference SNPs (rs9635726, rs2060941, rs907092, rs12946510, rs1453559, and rs62066988) were genotyped in 692 patients who had ALL (cases) and in 926 controls. The associations between IKZF3 polymorphisms and ALL risk were determined using odds ratios (ORs) and 95% confidence intervals (CIs). The associations of rs9635726 and rs2060941 with the risk of ALL were further estimated by using false-positive report probability (FPRP) analysis. Functional analysis in silico was performed to evaluate the probability that rs9635726 and rs2060941 might influence the regulation of IKZF3. The authors observed that rs9635726C>T (adjusted OR, 1.49; 95% CI, 1.06-2.11; p=.023) and rs2060941G>T (adjusted OR, 1.51; 95% CI, 1.24-1.84; p=.001) were related to and increased risk of ALL in the recessive and dominant models, respectively. Furthermore, the associations of both rs9635726 (FPRP=.177) and rs2060941 (FPRP<.001) with ALL were noteworthy in the FPRP analysis. Functional analysis indicated that rs9635726 and rs2060941 might repress the transcription of IKZF3 by disrupting its binding to MLLT1, TAF1, POLR2A, and/or RAD21. This study revealed that IKZF3 polymorphisms were associated with increased ALL susceptibility in children and might influence the expression of IKZF3 by disrupting its binding to MLLT1, TAF1, POLR2A, and/or RAD21. IKZF3 polymorphisms were suggested as a biomarker for childhood ALL.

Prognostic Features of CD9 in Childhood Acute Lymphoblastic Leukemia - a Retrospective Analysis of a Nation-Wide Multicenter Study in China

Background and objectives: The outcomes of children with acute lymphoblastic leukemia (ALL) have been incrementally improved with risk-directed chemotherapy but therapy responses remain heterogeneous in clinically defined risk groups. Parameters with added prognostic values are therefore warranted to refine the current risk stratification system and inform appropriate management. CD9, a cell surface protein presented on malignant lymphoblasts, may have such predictive characteristics as shown by our previous single-center study conducted in Hong Kong (Leung et al, Leukemia, 2020). This study aims to determine the precise prognostic features of CD9 in a nation-wide, multicenter childhood ALL cohort in China, and deliver algorithms for identification of patients who may benefit from early interventions. Study design and outcome measures: This multicenter cohort study included childhood ALL patients (aged &amp;lt;18 years) enrolled into the Chinese Children Cancer Group (CCCG)-ALL-2015 study from January 2015 to December 2019, with 7,640 patients from 20 tertiary hospitals in China treated with a uniform protocol. A total of 3,781 subjects (49.5%) from 16 sites had flow cytometry data on lymphoblast CD9 at diagnosis. The final study cohort comprised 3,395 B-ALL and 386 T-ALL patients with a median follow-up of 53.9 months. The primary outcomes were 5-year overall survival (OS), event-free survival (EFS), and cumulative incidence of relapse (CIR) for patients with CD9 + or CD9 - phenotypes (positivity defined by the presence of ≥20% CD9 + blasts evaluated through a univariate analysis demonstrating the highest odds for adverse events or relapse at this cut-off). The secondary outcomes were 5-year OS, EFS, and CIR rates of CD9 + and CD9 - patients after inclusion of known prognostic factors, including risk assignment, cytogenetic anomalies, and minimal residual disease (MRD) status. Survival benefits of CD9 + subjects from treatment intensification or hematopoietic stem cell transplantation (HSCT) were analyzed. Results: CD9 was expressed in 88.5% of B-ALL and 27.9% of T-ALL cases. It conferred a dismal EFS (82.1% vs. 89.3%, P=0.001) and a higher CIR (15.5% vs. 7.8%, P&amp;lt;0.001) in B-ALL but not T-ALL patients. The prognostic impact of CD9 is much more prominent in subjects with adverse presenting features or poor early treatment responses, as best exemplified in those assigned to the intermediate/high-risk arms (EFS: 72.8% vs. 83.2%, P=0.028; CIR: 23.1% vs. 10.2%, P=0.003) or those with positive MRD at day 19 (EFS: 65.2% vs. 82.0%, P=0.053; CIR: 30.3% vs. 9.7%, P=0.007). The adverse impact of CD9 is confined to specific cytogenetics, including BCR-ABL1 (CIR: 39.5% vs. 0%, P=0.019) and normal karyotype (CIR: 15.0% vs. 6.8%, P=0.034). In multivariate analyses, CD9 remains an independent factor predicting event-free survival (HR=1.917, P=0.001) and relapse (HR=2.208, P&amp;lt;0.001). The time to and site of relapse did not differ between CD9 + and CD9 - patients. For CD9 + patients with MRD at the end of induction, treatment upstaging only benefited initial low-risk subjects. HSCT at first remission did not improve the outcomes of high-risk subjects with a CD9 + phenotype. Conclusions: This is the largest study to evaluate the significance of CD9 in childhood ALL. We confirmed the results of our previous single-center study with this multicenter national study. CD9 positivity is definitively associated with a higher relapse probability particularly for patients with intermediate/high risk diseases, MRD positivity or specific cytogenetic background. BCR-ABL1 + patients with a CD9 - phenotype had excellent outcomes and HSCT may not be required. Whereas MRD + patients who were CD9 + had poor outcomes, and therefore should have early interventions with innovative treatments to reduce the risk of relapse. With these, we propose to incorporate CD9 into the diagnostic immunophenotyping panel to inform risk stratification and management of childhood ALL.

Association between BMI and Survival in Adolescents and Young Adults (AYA) with Acute Myeloid Leukemia Treated with Intensive Chemotherapy

Introduction: Obesity is linked to a higher incidence of acute myeloid leukemia (AML) in older adults as well as B-cell acute lymphoblastic leukemia in children and adolescents and young adults (AYA). To date, however, the relationship between weight and clinical outcomes in AYA patients (pts) diagnosed with AML has not been clearly established. We hypothesized that obesity reflected by higher body mass index (BMI) would confer worse prognosis in AYA pts treated with intensive chemotherapy and/or allogeneic stem cell transplant (SCT) for AML. Methods: We conducted a single institute retrospective chart review of AYA patients aged 18 to 39 years diagnosed with AML between Jan 2006 and Oct 2022. All patients received intensive chemotherapy with cytarabine- and anthracycline-based induction and consolidation chemotherapy followed in some cases by SCT. BMI was calculated based on height and weight on the date of AML diagnosis. Additional information including European Leukemia Net (ELN) 2022 risk classification, therapy response (complete remission (CR), CR with incomplete count recovery [CRi]), receipt of SCT, relapsed disease, event-free (EFS), overall survival (OS) and percentage of pts alive at 2- and 5-years after diagnosis were collected. All data was de-identified and procured on an IRB-approved protocol. Results: Seventy-six AYA patients were identified. Median age was 25.2 (range 18-39) years. 39 (51%) were female. The majority (65, 86%) were Caucasian. Per ELN 2022 risk classification, 24 (32%) had favorable, 36 (47%) had intermediate, and 16 (21%) had adverse risk disease. The CR rates based on ELN 2022 risk classification were 86%, 72% and 50%, respectively. Median OS for all pts was 791 days and per risk group was 1379, 569, and 595 days, respectively. Pts were then categorized per initial BMI into 4 categories. The majority of pts (44, 58%) had above average BMI (≥ 25), with 21 (28%) considered overweight with BMI 25-29.9 and 23 (30%) obese defined as BMI &amp;gt;30. Only 3 pts (4%) were underweight with BMI &amp;lt;18.5 (Table 1). Of note, 43% of obese pts had ELN favorable risk vs 33% of overweight pts and 24% of normal weight pts. Overall response rates in each BMI category were similar, ranging from 96-100% except in overweight pts where only 6 of 21 pts (29%) obtained CR. Relapse occurred in approximately one third (29-35%) of pts in the three highest BMI categories. Two thirds of all pts with BMI ≥18.5 underwent SCT. Excluding underweight pts due to small numbers (n=3), there was a trend to decreased survival in pts with BMI ≥18.5. Median overall survival among normal, overweight, and obese pts was 1403, 1295, and 777 days, respectively, with a significant difference between healthy and obese pts (p-value 0.0274 by log rank test). The percentage of pts alive after 5 years was 41%, 29%, and 17%, respectively (Table 2). Conclusion: Our real-world single-institute retrospective analysis suggests that AYA pts aged 18-39 yrs old diagnosed with AML and with higher BMI have decreased overall survival following intensive chemotherapy and/or allogeneic transplant. Obese patients with the highest BMI (&amp;gt;30) had a markedly shorter overall survival (median 777 days) and lower percentage of pts (17%) alive after five years following therapy than AYA AML pts with normal BMI (median 1403 days, 41% 5-year survival). This was despite over 40% of obese pts having favorable ELN risk. Potential reasons for this include biological heterogeneity in BMI cohorts, chemotherapy dosing, weight-related medical co-morbidities (i.e. cardiovascular disease) and/or transplant-related complications leading to shorter survival. Additional analyses to rule out the contribution of these and other factors and to confirm these results in a larger cohort are ongoing.

Increased Environmental Temperature Is an Emerging Health Risk That Correlates with Rates of Acute Lymphoblastic Leukemia in Europe

Background: The World Meteorological Organization (WMO) has calculated that European temperatures have increased at more than double the global average over the last 30 years 1. Besides research in radiation, little research has focused on how this might connect to the mechanisms initiating mutations in ALL. Both latitude and solar irradiance are potential risk factors in the development of ALL 2,3. Latitude covaries with the intensity of solar irradiance and ambient temperature, and both could therefore influence the risk of ALL. Furthermore, high ambient temperature during pregnancy was found to be associated with increased likelihood of childhood ALL 4. Global increases in temperature escalate the likelihood of extreme heat events, which in mammals increases reactive oxygen species, increases DNA damage, and suppresses the immune system 5. Few studies have evaluated changes in ambient temperature as a risk factor for ALL in Europe. We also included chronic lymphocytic leukemia (CLL) for comparison. Objective:To investigate the relationship between population-weighted country centroids (location of greatest population density), average country yearly temperature, solar irradiance and ALL and CLL rates in 40 European countries between the years 2010 and 2019. Design/Method:Incidence and prevalence rates for ALL and CLL (Age-standardized data with males and females) were obtained from the Global Health Data Exchange (GHDx) database. Population-weighted latitude/longitude centroids for Europe 6 were obtained from Baylor University and input into the Global Solar Atlas to obtain the average yearly global horizontal irradiance values. European temperature data was obtained from the Climatic Research Unit at the University of East Anglia (Copernicus Climate Data Store) 7. ALL and CLL incidence and prevalence rates per 100,000 people for 40 European countries were compared by linear regression to each country's temperature or solar irradiance at the population centroids. Statistical analyses were performed using GraphPad Prism and Excel. Results:After2010, we detected a significant positive correlation between ALL incidence and prevalence rates with mean annual temperature across countries for each year of analysis (for example in 2014 the ALL prevalence p-value = 0.01 and R= 0.4, see Figure 1). There was also an increase in the significance of this relationship over time between 2010 and 2019 (Figure 1B). We also detected a significant positive correlation between the increase in mean annual temperature across Europe and an increase in ALL over the past decade (Figure 1B). However, no relationship was established in this study for solar irradiance or population-weighted latitude and CLL prevalence and incidence rates. Conclusions:Increasing mean annual temperatures may increase the risk of developing ALL. We speculate this may be connected through increases in extreme weather events impacting oxidative stress, DNA damage, and/or suppression of the immune system. Considering the global climate crisis, the WMO finding of higher European temperature increases and our finding of significance between temperature and ALL rates, these relationships should be functionally studied. Finally, these studies should be expanded to countries outside of Europe. References 1 World Meteorological Organization. Temperatures in Europe increase more than twice global average. (2022). 2 Pordanjani, S. R., Kavousi, A., Mirbagheri, B., Shahsavani, A. &amp; Etemad, K. Temporal trend and spatial distribution of ALL in Iranian children during 2006-2014: a mixed ecological study. Epidemiol. Health42, (2020). 3 Coste, A. et al. Residential exposure to UV light and risk of precursor B-cell ALL: assessing the role of individual risk factors, the ESCALE and ESTELLE studies. Cancer Causes Control28, 1075-1083 (2017). 4 Rogne, T. et al. High Ambient Temperature in Pregnancy and Risk of Childhood ALL. medRxiv (2023) 5 Chauhan, S. S., Rashamol, V. P., Bagath, M., Sejian, V. &amp; Dunshea, F. R. Impacts of heat stress on immune responses and oxidative stress in farm animals and nutritional strategies for amelioration. Int. J. Biometeorol.65, 1231-1244 (2021). 6 Hamerly, G. Population-weighted European state centers. (2006). 7 Climatic Research Unit, U. of E. A. Temperature and precipitation gridded data for global and regional domains derived from in-situ and satellite observations. (2023).

Results of a Prospective Phase II Study of Individualized 6-Mercaptopurine Dosing Based on Pharmacogenomics in Childhood Acute Lymphoblastic Leukemia in East Asia

Introduction Variations in the NUDT15 and TPMT genes, which serve as pharmacogenomic markers for 6-mercaptopurine (6MP), contribute to individual differences in the optimal dosage of this medication. Nevertheless, given the observed difference in the tolerated dose of 6MP between East Asian and Western patients, it is essential to conduct a study to determine whether the same dosage guidelines are applicable to both populations. This study aimed to reduce treatment discontinuation and neutropenia during maintenance by adjusting the initial dose of 6MP based on the results of the NUDT15 or TPMT variants. M ethods This is a prospective phase II trial being conducted at three institutions in Korea. Patients who initiated 6MP-based maintenance treatment for acute lymphoblastic leukemia (ALL) were included in the study. During the maintenance phase, 6MP was administered at an individualized starting dose based on the NUDT15 and TPMT variants of each participant. Original dose (50 mg/m 2/day) of 6MP was administered to patients with both NUDT15 and TPMT wild-type, 30 mg/m 2/day for NUDT15 intermediate activity ( NUDT15 variant allele heterozygous) or TPMT heterozygosity, 10 mg/m 2/day for NUDT15 low activity ( NUDT15 variant allele homozygous), and 10 mg/m 2/day three times per week for homozygous TPMT variants. The maintenance cycle consists of 12 weeks of daily 6MP at an individualized dosage, weekly methotrexate (MTX) at a dosage of 20 mg/m 2, and monthly vincristine and steroid pulses. Lastly, intrathecally administered MTX is administered every three months. During treatment, the total white blood cell count was targeted to be between 2000/uL and 3000/uL, with an absolute neutrophil count greater than 500/uL and a platelet count greater than 50,000/uL. The whole exome was sequenced using genomic DNA extracted from peripheral blood at complete remission or hair follicles. As the primary and secondary endpoints, the duration of treatment discontinuation, the frequency of neutropenia, the presence of neutropenic fever during maintenance therapy, and the recurrence rate were compared to historical controls. A cohort of 254 patients who underwent maintenance therapy between the years 2001 and 2018 was chosen as the historical control group. Results Total 72 patients were enrolled from July 2019 until Aril 2022. This analysis was conducted on 52 patients who finished maintenance therapy. There were 32 males, and 20 females. The median age of the patients was 5.6 years (range, 2.2~15.9 years). The immunophenotypes of ALL was B-ALL in 40 patients, T-ALL in 10, Mixed phenotype in 1, and unspecified ALL in 1 patient. No patient had known pharmacogenetic variants in TPMT. The NUDT15phenotypes based on diplotypes included normal activity (n=41), intermediate activity (n=9), and low activity (n=2), occurring in 78.8%, 17.3%, and 3.8% respectively (Table 1). The number of days discontinued due to any toxicity during the 1 st cycle of maintenance therapy was average 7 days (max 59 days) in all patients, and that of the study group with intermediate enzyme activity phentypes was significantly shorter than in historical controls, with an average 6 days vs. 12 days ( P=0.03, Figure 1). The incidence of neutropenia during the 1 st cycle between two groups was not statistically different, however, among patients with NUDT15 or TPMT intermediate activity, the frequency of neutropenia was significantly lower in the study group ( P=0.03, Figure 2). The frequency of neutropenic fever (NF) and fever without neutropenia during the 1st cycle did not differ between the two groups. However, when patients with NUDT15 or TPMT intermediate activity were analyzed, no fever occurred in the study group of 9 patients, while NF and fever occurred in 11 and 8 patients in the control group (Figure 3). Conclusions Individualized administration of 6MP based on NUDT15 and TPMT genotypes during maintenance therapy in Korean pediatric ALL patients significantly reduced treatment discontinuation and febrile toxicity. A decrease in the initial dosage from 50 mg/m 2/day to 30 mg/m 2/day has the potential to reduce febrile toxicity in the patient group exhibiting intermediate activity of the NUDT15 enzyme, which is observed in approximately 20% of individuals in East Asia. Through this research, we expect to provide the dosing guidelines for 6MP in patients with ALL in East Asia.

CDK12/13: A Promising New Therapeutic Target in ALL

Acute lymphoblastic leukemia (ALL) is an aggressive hematologic malignancy in children and young adults. Upfront resistance to glucocorticoids used as first-line treatment in most regimens confers a poor prognosis for patients with ALL. Of patients who relapse, only half achieve long-term survival. Here we demonstrate that inhibition of cyclin dependant kinases 12 and 13 (CDK12 &amp; CDK13), which are modulators of RNA polymerase II, has a robust synergistic anti-leukemia effect with dexamethasone, in both B-ALL and T-ALL cell lines as well as primary B-ALL patient-derived bone marrow samples. To understand the mechanism underlying the steroid resistance in ALL, we first reanalyzed shRNA screen performed by Poulard et al. This revealed that CDK13 silencing sensitized leukemic cells to dexamethasone. CDK12 is located on chromosome 17q12, containing oncogenic features and genetic alterations in various tumors. CDK12/13 inhibitor exhibits efficacy against an Ewing sarcoma tumor growth in a patient-derived xenograft mouse model. It was shown that the inhibition resensitizes HER2+ breast cancers to HER2-tyrosine kinase inhibitors via suppressing PI3K/AKT in patient-derived organoids in vitro and cell-derived xenograft or patient-derived xenograft in vivo. Forgoing research demonstrates that CDK12/13 inhibition silences transcription of DNA damage response (DDR) genes. In our study, however, we haven't observed a rise in γH2AX, a marker of DNA damage, after CDK12/13 inhibition in ALL cell lines. What we did note was a marked enhancement expression of BIM and SGK1, steroid responsive genes and pro-apoptotic factors, after CDK12/13 inhibition (Figure A). ALL cell lines exhibited high susceptibility to CDK12/13 inhibition with two chemically divergent inhibitors, SR-4835 and THZ-531. We also showcased their synergistic interactions with dexamethasone using flow cytometry and synergyfinder ZIP score analysis (Figure B). Moreover, in the GSEA comparison of ALL cell lines with and without synergy between CDK12/13 inhibitors and dexamethasone, our data underscored significant enrichment in cholesterol biosynthesis-related genesets in cell lines manifesting this synergistic effect. On the other hand, we observed resistance to SR-4835 in cell lines with high enrichment scores in NOTCH, a signaling pathway implicated in about 80% of relapsed T cell ALL/LBL cases. Additionally, new data on mice xenotransplanted with B-ALL CNS-derived patient cells, link upregulated cholesterol biosynthetic pathways to nervous system involvement in childhood ALL. Upon administering CDK12/13 inhibitors, we observed a cell cycle phase shift resulting in G1 arrest and increased apoptosis, whereas human peripheral blood mononuclear cells (PBMCs) from healthy individuals remained unaffected by this treatment. As we continue to decode the pathways through which CDK12/13 inhibitors render ALL cells more susceptible to dexamethasone, our next step includes silencing CDK12/13 using short hairpin RNA models in cell lines and consequently their RNA sequencing. This approach may mitigate the influence of secondary pathways, paving the way for enhanced treatment strategies for relapsed ALL by unmasking the underlying molecular events.

Heritable Variation in Lymphocyte-Related Traits and Risk of Down Syndrome Acute Lymphoblastic Leukemia: A Mendelian Randomization Study

Introduction: The risk of developing acute lymphoblastic leukemia (ALL) is up to 30-fold higher in children with Down syndrome (DS). While trisomy 21 increases the risk of leukemia, only ~1% of children with DS develop ALL (DS-ALL), suggesting that additional modifying risk factors exist. A recent study in individuals without DS revealed that a genetic propensity for increased lymphocyte production was associated with an increased risk of childhood ALL. Additionally, a previous genome-wide association study (GWAS) of DS-ALL identified associations in genes involved in lymphoid development. Here, we investigated whether genetic variation in lymphocyte-related traits is associated with DS-ALL risk, with the hypothesis that a genetic predisposition for lymphocyte overproduction is associated with an increased risk of DS-ALL. Methods: We performed Mendelian randomization (MR) analyses to investigate the potential causal relationship between variation in four lymphocyte-related traits - lymphocyte counts, the lymphocytes to monocytes ratio (LMR), the neutrophils to lymphocytes ratio (NLR), and the platelets to lymphocytes ratio (PLR) - and DS-ALL risk. Genetic variants associated with each lymphocyte-related trait (“exposure”) at P &amp;lt; 5x10 -8 and their corresponding effect sizes and standard errors were obtained from GWAS of blood cell traits performed in 413,810 cancer-free individuals of European ancestry in the UK Biobank. A GWAS of DS-ALL (“outcome”) was carried out using germline whole-genome sequencing data from 222 DS-ALL cases and 1,010 individuals without ALL from DS research cohorts, limited to individuals of non-Hispanic White race/ethnicity. We examined consistency across multiple MR methods, including the inverse-variance weighted (IVW), weighted median (WM), MR robust adjusted profile score (RAPS), and MR pleiotropy residual sum and outlier (PRESSO) estimators. Results: Among the lymphocyte-related traits, we found a significant association between LMR and DS-ALL risk that was consistent across MR estimators. Specifically, each 1-unit increase in LMR was associated with a 41%-53% decrease in ALL risk in children with DS (odds ratio [OR IVW] = 0.56; 95% CI: 0.35-0.90, p = 0.016; OR WM = 0.47; 95% CI: 0.21-1.04, p = 0.051; OR RAPS = 0.59; 95% CI: 0.36-0.97, p = 0.038; OR PRESSO = 0.55; 95% CI: 0.34-0.88, p = 0.014). There were no statistically significant associations between the remaining blood cell traits (lymphocyte count, PLR, and NLR) and DS-ALL risk, although increased lymphocyte counts conferred a modest increase in risk of DS-ALL (OR IVW=1.24, p=0.40). Conclusions: We discovered that genetic predisposition to shifts in the ratio of lymphocytes relative to monocytes may be a novel risk factor for the development of DS-ALL, with a deficit of lymphocytes to monocytes conferring an increased risk of DS-ALL. This observed direction of effect contrasts with previous findings for ALL in the non-DS population, suggesting a distinct etiology of ALL in the context of DS that may be influenced by the profound effects of trisomy 21 on immune function. Replication of our findings in independent DS-ALL studies is underway, and analysis of polygenic risk scores for lymphocyte traits may further improve identification of children with a high risk of DS-ALL.

The Relapse Mechanisms and Genomic Landscape Differ in KMT2A-r Pediatric Leukemia in Relation to Relapse Time

The genomic landscape and mechanisms driving relapse in KMT2A-rearranged ( KMT2A-r) infant and childhood acute lymphoblastic (ALL) and acute myeloid leukemia (AML) are not completely understood. We therefore studied 36 KMT2A-r ALL (n=19) and AML (n=17) patients of which 25 relapsed and 11 remained in remission. Twenty diagnose-relapse-germline trios and 5 multiple relapse samples were analyzed by whole genome (WGS) and whole exome sequencing (WES) and 30 patients longitudinally by using patient-specific mutations identified by WGS/WES, including the KMT2A-r (average coverage 3300X). The mutational burden increased from diagnosis to relapse and relapse evolved through branching evolution. Relapse was seeded by multiple diagnostic clones in 56%, by a single sweeping clone detected at diagnosis in 22%, and by a single sweeping clone not detected at diagnosis in 22%. Notably, the evolutionary patterns correlated to relapse time, where multiple diagnostic clones seeding relapse were connected to an earlier relapse with all very early relapse ALL (3/3, relapse &amp;lt;9 months from diagnosis) and half of the early AML relapse showing this pattern (2/4, relapse &amp;lt;1 year in complete remission, CR1). By contrast, later relapse was connected to a sweeping clone at relapse with 67% of early relapse ALL (&amp;gt;9 months from diagnosis) and 40% of late relapse AML (&amp;gt;1 year in CR1) showing this pattern. Pathway analysis showed that cell cycle genes, glucocorticoid signalling, purine metabolism, mismatch repair, and B-cell differentiation, were enriched in early relapse ALL (83%, 5/6) and included TP53, CREBBP, NT5C2 PMS2, PRPS2, NR3C1, IKZF1, with none of the very early relapse infant ALL harboring such alterations (n=4). Further, TP53 and IKZF1alterationsco-occurred (n=4/4). These results were validated in public data sets of 98 KMT2A-r ALL infants (n=84) and children (n=14) at diagnosis and relapse (n=24) and showed that 50% of early relapse ALL, and none of the 8 very early relapse ALL, had such alterations. Ultra-deep sequencing did not detect the CREBBP, NT5C2, PRPS2or TP53 mutations at diagnosis and manual inspection of the WGS reads failed to detect the PMS2 and NR3C1 deletions. In AML, TP53 and CCND3 alterations were maintained, and gain of WT1 was seen in late relapse AML. Signalling mutations were the most common type of mutations at diagnosis (64%) and relapse (56%) and the frequency was similar in patients that remained in remission and in those that relapsed (55% versus 60%). One infant ALL and four AML patients had multiple relapses, allowing us to study how the genetic landscape evolved across consecutive relapses. This showed a stepwise replacement of clones during treatment in agreement with a fitter clone that evolves under chemotherapeutic selective pressure. Longitudinal analysis allowed sensitive detection of residual leukemia cells and showed that the relapse clone could be detected at diagnosis in 64% of patients. Further, infants with &amp;gt;10% of molecularly detectable leukemia cells after induction therapy, had a high risk of a very early relapse. Ultra-deep sequencing allowed detection of the relapse clone up to 4 months before relapse. In 11 of the 30 patients (3 remission and 8 relapse), low-frequency KMT2A-fusion positive leukemic cells were found at remission outside of the MRD time points. Our longitudinal data also provided unique insights into clonal response to treatment by showing that 1) a change in therapy can favour the eradication of one clone and expansion of another, 2) a clone that initially was the most sensitive clone to therapy, was the one that eventually caused relapse, and 3), a diagnostic clone can be undetectable for a long time before expanding to cause relapse, suggesting that molecular monitoring with personal mutations is a powerful tool to follow response to therapy. These results provide new biological insights into the relapse mechanisms in KMT2A-r leukemia. The data shows different clonal evolution patters depending on when in time the patient relapsed, with very early relapse ALL being seeded by multiple diagnostic subclones and a paucity of acquired genetic alterations at relapse. By contrast, early relapse ALL was characterized by a single diagnostic clone seeding relapse by a clonal sweep along with acquired mutations in chemoresistance-associated genes. To validate and extend these findings, we are currently analyzing 11 additional infant relapse samples with WGS.

Zegocractin to Reduce the Severity of Asparaginase Associated Pancreatitis in Children with Acute Lymphoblastic Leukemia: Results of the Phase 1 Portion of the Crspa Study

INTRODUCTION Asparaginase-associated pancreatitis (AAP) is one of the most severe and dreaded complications during therapy of childhood acute lymphoblastic leukemia (ALL). It is characterized by intense abdominal pain, nausea/ vomiting, and systemic inflammatory response syndrome. AAP can result in chronic complications such as insulin dependence, exocrine pancreatic insufficiency, and chronic pain. These symptoms are more common when pancreatic necrosis or pancreatic pseudocysts develop immediately after AAP. Treatment for AAP has historically been limited to supportive care. However, a novel calcium release activated calcium channel blocker, zegocractin (formerly CM4620), currently in clinical trials in adults with pancreatitis, may reduce the severity of AAP. We thus developed the phase 1/2 CRSPA study to identify the recommended phase 2 dose (RP2D) of zegocractin in children and young adults with AAP during ALL treatment. METHODS To investigate the characteristics of AAP in the absence of zegocractin, we retrospectively evaluated patients treated on the Total Therapy XVI study (T16) who developed pancreatitis within 30 days of receiving asparaginase (AAP). In the CRSPA trial, patients with ALL experiencing AAP were offered trial enrollment and provided informed consent/ assent. Participants underwent initial CT either prior to or on day 1 of CRSPA therapy. Zegocractin was administered as a 4-hour infusion on days 1-4 starting at dose level 1 (30mg/m 2 on day 1 and 42mg/m 2 on days 2-4), with dose limiting toxicities (DLT) defined as any CTCAE grade 3-5 toxicity not attributable to either pancreatitis or ALL therapy. Planned dose escalation was guided by a Keyboard design. The primary efficacy endpoint of the study focused on the occurrence of pancreatic necrosis or pseudocyst on CT after day 28. RESULTS Among 598 patients treated on T16, 51 (8.5%) developed AAP. The mean age at AAP onset was 10.3 (range 2.2-21.4) years; 34 were male and 17 were female. 9 received low-risk therapy while the remainder were on standard- or high-risk therapy. Adequate follow-up imaging was available for 39 patients. Of these, 22 (56% of those with imaging, 43% of all AAP patients) had peri-pancreatic fluid collections (PPFC; N=18) and/or pancreatic necrosis (N=14). Mean hospitalization was 12.1 days (range 2-70), mean ICU time in the 11 (21.6%) patients requiring ICU care was 5.1 days (1-9), and mean duration of total parenteral nutrition (TPN) in the 27 (52.9%) patients needing it was 37.7 days (3-153). Among the 9 patients (median age 8.8, range 3.1-17.6 years) treated in the first cohort of the Keyboard design phase 1 portion of CRSPA, 1 had a DLT (infusion reaction during dose 1) characterized by ill feeling and shortness of breath. The infusion was stopped and diphenhydramine was administered with symptomatic improvement. However, the symptoms recurred and worsened as the patient's AAP symptoms worsened. The event was retrospectively felt to be related to AAP rather than study medication, but it remained as a DLT. None of the other 8 patients treated at dose level 1 experienced a DLT. Pharmacokinetic analysis indicated that drug exposure at dose level 1 was at least as high as that seen in adults treated at the adult RP2D (i.e. 2 mg/kg on days 1-2 and 1.6 mg/kg on days 3-4). Because dose level 1 was well tolerated, we amended the protocol and evaluated whether there was a preliminary efficacy signal prior to dose escalation. Among the 8 patients who received all 4 doses and were evaluable for efficacy, 1 had a small PPFC and none had significant pancreatic necrosis on follow-up imaging; mean hospitalization was 6.3 days (range 5-8), 1 patient needed ICU care (3 days), and none required TPN. To further assess preliminary efficacy, CTs from the T16 cohort were matched on sex and age with CRSPA patients at a 2:1 ratio and were evaluated by a blinded radiologist. The mean CT severity index was 5.4 in the historical controls vs. 2.4 in the CRSPA patients evaluable for efficacy. CONCLUSION Patients with AAP receiving supportive care in the historical T16 cohort experienced a high rate of pancreatic necrosis and pseudocyst. The CRSPA study established dose level 1 as the RP2D of zegocractin for children with ALL experiencing AAP. The phase 1 portion of the study has provided promising data on zegocractin efficacy. Moving forward, the ongoing phase 2 portion of the study will further assess and validate the efficacy of zegocractin in treating AAP.

The Different Impacts of an MRD-Guided Protocol on Relapse of Childhood Acute Lymphoblastic Leukemia: The Report of Taiwan Pediatric Oncology Group (TPOG)-ALL-2013

Taiwan Pediatric Oncology Group (TPOG)-ALL-2013 protocol (TPOG-2013), modifying from St. Jude Total Therapy XV Study and Total Therapy XVI Study, was launched since January 2013. This is the first nationwide minimal residual disease (MRD)-directed protocol for treatment of childhood acute lymphoblastic leukemia (ALL) in Taiwan. According to TPOG-2013, two MRD measurements were scheduled on days 15-19 of induction (MRD1 time point, TP1) and days 35-42, end of induction (MRD2 time point, TP2) to make the definitive risk stratification to guide subsequent therapy. As of April 30, 2023, 814 newly diagnosed ALLs treated with TPOG-2013 and followed up ≥3 years were enrolled in the study. The outcomes were compared with those of TPOG-ALL-2002 protocol (TPOG-2002) (N=1350, between January 2002 and December 2012), which did not integrate the MRD monitoring. The 5-year event-free survival and overall survival were significantly improved from 76% (95% CI, 74-78) and 81% (80-84) of TPOG-2002 to 86% (83-88) and 89% (87-92) of TPOG-2013, respectively ( P&amp;lt; 0.0001). For further analysis of TPOG-2013, 585 (72%) patients with exact adherence (EA) to both TPs were assigned as MRD EA group; 225 patients who were non-adherence (NA) to either one of TPs as MRD NA group; and four patients were excluded for the comparative outcome analysis. For B-cell precursor (BCP) ALL, the 5-year cumulative incidence of relapse (CIR) significantly decreased from TPOG-2002 (N=1194) to TPOG-2013 MRD EA (N=527) ( P &amp;lt;0.0001). However, there was no significant improvement of CIR between TPOG-2002 and MRD NA (N=202) ( P= 0.21) (Figure 1). In MRD EA of BCP-ALL, compared with TPOG-2002, patients with ETV6::RUNX1 or BCR::ABL1 appeared to have significantly lower CIR. Patients without the common genetic subtypes , denoted as “negative” group, also had significant inferior CIR. And the trend of CIR decrease did not attain significant difference in high hyperdiploidy. In contrast, patients with T CF3::PBX1 or infant with KMT2A-rearrangement did not show CIR improvement (Table 1). In T-ALL, compared with TPOG-2002 (N=156), there was a significant decrease of CIR in TPOG-2013 MRD EA (N=58)( P= 0.01)(Table 1), but not in MRD NA (N=23)( P= 0.86). There was a longer duration to relapse in MRD EA of BCP-ALL. However, a delay of relapse was only demonstrated in patients with BCR::ABL1, which could be addressed by the introduction of MRD-monitoring and TKI inhibitor in TPOG-2013 (Table 1). Further, in term of early relapse before 1.5 year of remission, there was no significant difference in MRD EA of BCP-ALL, compared with TPOG-2002. In conclusion, this study demonstrated diffident impacts on relapse according to genetic subtypes and MRD adherence. In the negative group of BCP-ALL without the discovery of novel genetic alternations, the relapse could be much decreased with the MRD-directed treatment protocol.