Childhood B-acute Lymphoblastic Leukemia Research Articles

Attention and executive functioning in children and adolescents treated for high-risk acute lymphoblastic leukemia: A report from the Children's Oncology Group (COG).

Survivors of childhood B-acute lymphoblastic leukemia (B-ALL) are at risk for difficulties with attention and executive functioning (EF) as a late effect of treatment. The present study aimed to identify treatment and demographic factors associated with risk for difficulties with EF in youth treated for high-risk B-ALL. Children and adolescents with B-ALL treated on Children's Oncology Group (COG) protocol AALL0232 were randomized to high-dose or escalating-dose methotrexate (MTX), and either dexamethasone or prednisone during the induction phase. Neuropsychological functioning was evaluated via protocol AALL06N1, including performance-based and parent-report measures, for 177 participants (57% female, 81% white; mean age at diagnosis=8.4 years; SD=5.0) 8-24 months following treatment completion. Mean scores for all attention and EF measures were within the average range, with no significant differences as a function of MTX delivery or steroid treatment (all p >0.05). In multivariable models, participants with US public insurance exhibited significantly greater parent-reported EF difficulties than those with US private or non-US insurance (p ≤ 0.05). Additionally, participants diagnosed under 10 years of age performed significantly more poorly on measures of attention (i.e., continuous performance task, p ≤ 0.05) and EF (i.e., verbal fluency and tower planning task, p≤0.05). For survivors of pediatric B-ALL, treatment-related factors were not associated with attention or EF outcomes. In contrast, outcomes varied by demographic characteristics, including age and insurance type, an indicator of economic hardship. Future research is needed to more directly assess the contribution of socioeconomic status on cognitive outcomes in survivors.

Bispecific T-cell engagers in childhood B-acute lymphoblastic leukemia.

Immunotherapy has revolutionized treatment for a wide variety of cancers yet its use has been relatively limited in childhood malignancies. With the introduction of bispecific T-cell engagers (BiTE®) and chimeric antigen T-cell receptor technologies, previously refractory patients have attained remission, including molecularly negative states of disease, thus providing the possibility of long-term cure. Blinatumomab is a widely available CD3-CD19 BiTE that has dramatically changed the landscape of therapy for some children with precursor-B acute lymphoblastic leukemias (B-ALL) and lymphoblastic lymphomas. Challenges remain with using BiTE in a broader population although the appeal of now-confirmed reduced toxicity and deeper molecular remissions suggests that this approach will be an essential part of future treatment of childhood B-ALL. Herein, we review some of the pertinent literature covering clinical trials with blinatumomab and address future approaches and combination trials including BiTE.

SMYD2 Expression: Its Relationship to Cytogenetic and Prognosis in a Newly Diagnosed Childhood B-Acute Lymphoblastic Leukemia.

The SMYD2 gene adjusts lysine residues on histones and non-histone proteins such as transcription factors, signaling kinases, and cell cycle regulators affecting the cell fate and other genes' expression. As it acts as an oncogene, SMYD2's expression levels may affect tumor progression. In this prospective study, our main aim was to determine the association of SMYD2 gene expression with the prognostic parameters of childhood B-acute lymphoblastic leukemia (B-ALL) and evaluate its influence on disease prognosis. SMYD2 gene expression was measured in the peripheral blood (PB) samples of 116 newly diagnosed B-ALL patients and 23 controls using real-time polymerase chain reaction (RT-PCR). SMYD2 expression was significantly higher in the childhood B-ALL patients compared with the control group, p-value < 0.001. The patients with unfavorable rather than favorable structural chromosomal abnormalities had significantly higher SMYD2 mRNA levels, p < 0.001. SMYD2 expression levels were positively correlated with total leucocytes count (r = 0.206, p-value = 0.027) and peripheral blood blasts (r = 0.225, p-value = 0.015). There was a statistical difference between the B-ALL cases with high versus low SMYD2 levels regarding translocation (t12; 21), p-value = 0.015. Cox regression analysis identified the increased levels of SMYD2 as an independent prognostic factor affecting both OS and DFS. The SMYD2 gene plays a vital oncogenic role in childhood B-ALL. The association of high SMYD2 levels with unfavorable cytogenetics in childhood B-ALL may be helpful in understanding the relationship between structural chromosomal abnormalities and epigenetic dysregulation. High SMYD2 levels may be useful in the prediction of prognosis in childhood B-ALL.

Persistence of Chemotherapy-Induced Peripheral Neuropathy Despite Vincristine Reduction in Childhood B-Acute Lymphoblastic Leukemia.

Children with B-acute lymphoblastic leukemia (B-ALL) are at risk for chemotherapy-induced peripheral neuropathy (CIPN). Children's Oncology Group AALL0932 randomized reduction in vincristine and dexamethasone (every 4 weeks vs 12 weeks during maintenance in the average-risk subset of National Cancer Institute standard-B-ALL (SR AR B-ALL). We longitudinally measured CIPN, overall and by treatment group. AALL0932 standard-B-ALL patients aged 3 years and older were evaluated at T1-T4 (end consolidation, maintenance month 1, maintenance month 18, 12 months posttherapy). Physical and occupational therapists (PT/OT) measured motor CIPN (hand and ankle strength, dorsiflexion and plantarflexion range of motion), sensory CIPN (finger and toe vibration and touch), function (dexterity [Purdue Pegboard], and walking efficiency [Six-Minute Walk]). Proxy-reported function (Pediatric Outcome Data Collection Instrument) and quality of life (Pediatric Quality of Life Inventory) were assessed. Age- and sex-matched z scores and proportion impaired were measured longitudinally and compared between groups. Consent and data were obtained from 150 participants (mean age = 5.1 years [SD = 1.7], 48.7% female). Among participants with completed evaluations, 81.8% had CIPN at T1 (74.5% motor, 34.1% sensory). When examining severity of PT/OT outcomes, only handgrip strength (P < .001) and walking efficiency (P = .02) improved from T1-T4, and only dorsiflexion range of motion (46.7% vs 14.7%; P = .008) and handgrip strength (22.2% vs 37.1%; P = .03) differed in vincristine and dexamethasone every 4 weeks vs vincristine and dexamethasone 12 weeks at T4. Proxy-reported outcomes improved from T1 to T4 (P < .001), and most did not differ between groups. CIPN is prevalent early in B-ALL therapy and persists at least 12 months posttherapy. Most outcomes did not differ between treatment groups despite reduction in vincristine frequency. Children with B-ALL should be monitored for CIPN, even with reduced vincristine frequency.

NT5E gene and CD38 protein as potential prognostic biomarkers for childhood B-acute lymphoblastic leukemia.

The risk stratification of B-acute lymphoblastic leukemia (B-ALL) is based on clinical and biological factors. However, B-ALL has significant biological and clinical heterogeneity and 50% of B-ALL patients do not have defined prognostic markers. In this sense, the identification of new prognostic biomarkers is necessary. Considering different cohorts of childhood B-ALL patients, gene (DPP4/CD38/ENTPD1/NT5E) and protein (CD38/CD39/CD73) expressions of ectonucleotidases were analyzed in silico and ex vivo and the association with prognosis was established. In univariate analyses, expression of NT5E was significantly associated with worse progression-free survival (PFS) in bone marrow (BM) samples. In multivariate analyses, Kaplan-Meier analysis, and log-rank test, higher NT5E expression predicted unfavorable PFS in BM samples. Considering minimal residual disease (MRD), higher levels of cellularity were associated with the high NT5E expression at day 8 of induction therapy. In addition, we observed that white blood cells (WBC) of childhood B-ALL patients had more CD38 compared to the same cell population of healthy donors (HD). In fact, MRD > 0.1% patients had higher CD38 protein expression on WBC in comparison to HD. Noteworthy, we observed higher CD38 expression on WBC than blasts in MRD > 0.1% patients. We suggest that NT5E gene and CD38 protein expression, of the ectonucleotidases family, could provide interesting prognostic biomarkers for childhood B-ALL.

The role of CD58 and CD38 in evaluation of minimal residual disease in childhood B-acute lymphoblastic leukemia

Background: Measurement of minimal residual disease (MRD) reflects the overall response to therapy, and could be used to refine the treatment of acute lymphoblastic leukemia (ALL). MRD studies by flowcytometry rely on panels of antibodies (Abs) to define unique immunophenotypic signature of leukemic blasts. Aim: to evaluate the role of CD38 and CD58 in detection of MRD in childhood B-ALL. Results: The mean age in our patients was 6.7 years. They were 54% males and 46% females. At day 14 post induction, 25% of our patients were negative for MRD, while 75% were positive for MRD. CD38 under-expression was +ve in 66.7%, while CD58 overexpression was +ve in 50% of the patients at diagnosis. There was a significant increase in +ve CD38 under-expression among patients had +ve MRD. Also there was a significant increase in +ve CD58 overexpression among patients had -ve MRD. CD38 underexpression demonstrated than CD58 overexpression. Conclusion: CD38 is a hopeful marker that needs to be used routinely for assessment of MRD. It is more informative than CD58 in B-ALL patients. CD38 under-expression has higher frequency and less modulation than CD58 overexpression during remission induction therapy.

Impact of CD105 Flow-Cytometric Expression on Childhood B-Acute Lymphoblastic Leukemia

BackgroundCD105 (Endoglin) is a receptor of the transforming growth factor-Beta (TGF- β) superfamily. It is expressed in angiogenic endothelial cells and is considered a powerful marker of angiogenesis and a potential main player in the pathogenesis of vascular diseases as well as tumor progression. CD105 expression was correlated with poor prognosis in many types of solid malignancies, however, its influence on hematological neoplasms is still an area of interest.PurposeTo assess the flow-cytometric expression of CD105 in childhood B-acute lymphoblastic leukemia (B-ALL) and its relation to disease response after the induction chemotherapy.Subjects and MethodsEighty children newly diagnosed with B-ALL were screened for flow-cytometric expression of CD105 at time of diagnosis, then they were followed up to detect their response to induction therapy.ResultsCD105 was expressed in 41.2% of B-ALL patients. Higher expression of CD105 was observed in high and very high-risk groups. The multivariate analysis considered CD105 positivity as an independent prognostic marker for response to induction therapy. Values higher than 2.5 Specific fluorescence indices (SFIs) and 35% expression were sensitive predictors to induction failure.ConclusionCD105 can be considered as a potential prognostic marker for the detection of response to induction therapy in childhood B-ALL, and it can serve to optimize treatment decisions.

Therapeutic Targets in Childhood B-Acute Lymphoblastic Leukemia : What about HER2/Neu?

Relapsed B-lineage acute lymphoblastic leukemia (ALL) in children is associated with poor prognosis. Therefore, it seems essential to stratify patients according to prognostic factors in order to adapt therapies. The evaluation of minimal/measurable residual disease (MRD) during chemotherapy constitutes the most powerful prognostic factor in all age groups, indeed, patients with early low MRD having better outcomes. New immunotherapies based on monoclonal antibodies have recently been developed and are giving promising results in chemoresistant forms with limited toxicities. Indeed, CD20, CD38, CD22 and, less developed, HER2/neu constitute therapeutic targets. However, few studies have reported on the expression level of these markers and compared it to the normal counterpart, precursor B-cells or hematogones. Such investigations would be useful to appreciate the potential efficacy of immunotherapies targeting these markers. Moreover, it could help for the detection of minimal/measurable residual disease during follow-up. A cohort of 125 B-ALL patients (1-25 years old) was retrospectively enrolled in this study, treated between January 2011 and February 2020. Samples collected from bone marrow or peripheral blood were studied in multiparameter flow cytometry (MFC). Cells were analyzed with a Canto II flow cytometer (BD Biosciences), and Diva (BD Biosciences) software was used to assess the expression of the antigenic markers. The same MFC assay had been performed over the whole period, allowing for fluorescence intensities comparison. Additionally, results from 36 normal bone marrow samples were examined, to compare the level of antigen expression by hematogones. CD20, CD38 and CD22 were expressed in respectively 53.6%, 99.2% 98.4% of the cases, rather homogeneously and at intermediate levels. The mean fluorescence intensity of CD38 was much higher on hematogones than blasts, which made it a leukemia-associated immunophenotype (LAIP) for 101 patients (81.4%). HER2/neu, a marker of breast cancer also expressed in a subset of ALL, was present in 16 samples (13.4%), but not detectable on hematogones, and can thus always be considered a LAIP. Interestingly, in this subgroup, patients had a significantly lower 5-year EFS compared to patients without expression of HER2/neu (63% versus 80.5%, p=0.02) (Figure 1). No significant difference in the expression of tested potential therapeutic markers was found between age groups. In conclusion, these 4 antigens have sufficient expression intensities to make them potential therapeutic targets, which could be an interesting alternative for the treatment of refractory/relapsed childhood B-ALL. For example, trastuzumab could be a potential immunotherapy in the HER2/neu expressing group, especially regarding their poorer prognosis. Moreover, CD38 and HER2/neu are good candidates for monitoring MRD. These results are of interest as it has been shown that monitoring MRD early was prognostic on patients' outcome. Figure Disclosures Chevallier: Incyte Corporation: Honoraria.

An acquired stable variant of a dicentric dic(9;20) and complex karyotype in a Syrian childhood B-acute lymphoblastic leukemia case

BackgroundAbout 25 years ago, the acquired chromosome abnormality dicentric dic(9;20)(p11 ~ 13;q11) was seen described as a non-random aberration in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Yet, about 200 cases were reported. However, dicentric dic(9;20) is a subtle abnormality which easily may be mixed up with monosomy 20 and/or del(9p). The dicentric dic(9;20) can be found as a sole chromosomal abnormality or can be masked within complex rearrangements; also, a dicentric dic(9;20) is often associated with mono- or biallelic loss of CDKN2A gene.Case presentationHere we report a case of 16-year-old male diagnosed with a de novo pre-B-ALL. Molecular approaches (array-based multicolor banding (aMCB) and array comparative genomic hybridization (aCGH)) were applied, and a unique complex karyotype involving six chromosomes was identified. It included three previously unreported chromosomal aberrations: dicentric dic(9;20;X), deletion del(7)(p22.2p15.2) and dicentric dic(7;13). The dicentric dic(9;20;X) also led to monoallelic loss of tumor suppressor gene CDKN2A. After successful chemotherapeutic treatment the patient experienced a relapse with a secondary ALL without complex karyotype but a deletion del(19)(p13). Unfortunately, the patient died after 17 months of the initial diagnosis.ConclusionsTo the best of our knowledge, a comparable childhood ALL associated with such complex karyotype and deletion del(19)(p13) in secondary ALL was not previously reported. Thus, the complex karyotype with dicentrc dic(9;20;X) seems to indicate for a poor prognosis.

Outcomes after late bone marrow and very early central nervous system relapse of childhood B-acute lymphoblastic leukemia: a report from the Children's Oncology Group phase III study AALL0433

Outcomes after relapse of childhood B-acute lymphoblastic leukemia (B-ALL) are poor, and optimal therapy is unclear. The children’s Oncology Group study AALL0433 evaluated a new platform for relapsed ALL. Between March 2007 and October 2013 AALL0433 enrolled 275 participants with late bone marrow or very early isolated central nervous system (iCNS) relapse of childhood B-ALL. Patients were randomized to receive standard versus intensive vincristine dosing; this randomization was closed due to excess peripheral neuropathy in 2010. Patients with matched sibling donors received allogeneic hematopoietic cell transplantation (HCT) after the first three blocks of therapy. The prognostic value of minimal residual disease (MRD) was also evaluated in this study. The 3-year event free and overall survival (EFS/OS) for the 271 eligible patients were 63.6±3.0% and 72.3±2.8% respectively. MRD at the end of Induction-1 was highly predictive of outcome, with 3-year EFS/OS of 84.9±4.0% and 93.8±2.7% for patients with MRD <0.1%, versus 53.7±7.8% and 60.6± 7.8% for patients with MRD ≥0.1% (P<0.0001). Patients who received HCT versus chemotherapy alone had an improved 3-year disease-free survival (77.5±6.2% vs. 66.9 + 4.5%, P=0.03) but not OS (81.5±5.8% for HCT vs. 85.8±3.4% for chemotherapy, P=0.46). Patients with early iCNS relapse fared poorly, with a 3-year EFS/OS of 41.4±9.2% and 51.7±9.3%, respectively. Infectious toxicities of the chemotherapy platform were significant. The AALL0433 chemotherapy platform is efficacious for late bone marrow relapse of B-ALL, but with significant toxicities. The MRD threshold of 0.1% at the end of Induction-1 was highly predictive of the outcome. The optimal role for HCT for this patient population remains uncertain. This trial is registered at clinicaltrials.gov (NCT# 00381680).

SYK Targeting Represents a Potential Therapeutic Option for Relapsed Resistant Pediatric ETV6-RUNX1 B-Acute Lymphoblastic Leukemia Patients.

The presence of the chromosomal rearrangement t(12;21)(ETV6-RUNX1) in childhood B-acute lymphoblastic leukemia (B-ALL) is an independent predictor of favorable prognosis, however relapses still occur many years later after stopping therapy, and patients often display resistance to current treatments. Since spleen tyrosine kinase (SYK), a cytosolic nonreceptor tyrosine kinase interacting with immune receptors, has been previously associated with malignant transformation and cancer cell proliferation, we aimed to assess its role in ETV6-RUNX1 cell survival and prognosis. We evaluated the effects on cell survival of three SYK inhibitors and showed that all of them, in particular entospletinib, are able to induce cell death and enhance the efficacy of conventional chemotherapeutics. By using reverse phase protein arrays we next revealed that activated SYK is upregulated at diagnosis in pediatric ETV6-RUNX1 patients who will experience relapse, and, importantly, hyperactivation is maintained at a high level also at relapse occurrence. We thus treated primary cells from patients both at diagnosis and relapse with the combination entospletinib + chemotherapeutics and observed that SYK inhibition is able to sensitize resistant primary cells to conventional drugs. Entospletinib could thus represent a new therapeutic option supporting conventional chemotherapy for relapsed ETV6-RUNX1 patients, and these evidences encourage further studies on SYK for treatment of other relapsed resistant acute lymphoblastic leukemia (ALL) subgroups.

Hispanic and Black Patients with Adult B-Cell Acute Lymphoblastic Leukemia Have a Significantly Worse Survival in the Modern Era - a SEER 2010-2016 Analysis

Prior studies have evaluated incidence and survival trends for B-Acute Lymphoblastic Leukemia (B-ALL) in children and adults. However, there have been no recent studies evaluating the difference in survival between different race and ethnicities in the era of tyrosine kinase inhibitors and novel combination therapy. We wanted to determine 5-year observed survival for adult patients with B-ALL diagnosed in recent years and assess for any difference in survival by race-ethnicity. Methods: We used Surveillance Epidemiology End Results (SEER) 18 registry to identify B-ALL patients using ICD-O-3 codes 9811-9818 and 9836. SEER 18 covers ~28% of US population. The year of diagnosis was limited to 2010-2016 in order to capture a patient population most likely treated with modern therapies. We limited our study to adults aged 20 years (yrs) or more, which were then divided into the following age groups: 20-29, 30-39, 40-49, 50-59, 60-69,70-79,80+ yrs of age. Gender, race-ethnicity, median family income and observed overall survival (OS) were obtained from SEER. For multivariate survival analysis, Cox proportional hazard model was used to adjust for clinically important and other relevant variables (age, gender, race-ethnicity, median income). We included median family income, a county level characteristic in our analysis as a surrogate for access to care. We divided these counties into quintiles based on median family income and included that variable in the multivariate model. We did not adjust for genetic risk or patient insurance status, as the information provided in SEER was inadequate and would likely lead to misclassification bias. SEER Stat 8.3.5 and SAS student edition were used for analysis. Results: 4244 cases of B-ALL were identified with an age adjusted incidence rate of 0.92 per 100,000. B-ALL occurred at all ages, but incidence was higher in young adults (&amp;lt;30 yrs) and adults older than 50 yrs of age, with peak incidence noted in the oldest age group (80+yrs). Of note, our cohort included adults older than or equal to 20 yrs of age, hence did not capture the early peak of childhood B-ALL. Females had a statistically significant lower incidence of B-ALL as compared to males (Incidence rate ratio (IRR) 0.77, p-value&amp;lt;0.05). Table 1 lists counts and IRR by different patient characteristics. Age adjusted incidence was the highest among Hispanics (1.61{1.53-1.71}), followed by Non-Hispanic Whites (NHW)(0.77{0.73-0.8}, Non-Hispanic Asian Pacific Islander (NHAPI)(0.7{0.63-0.78}) and Non-Hispanic Blacks (NHB)(0.54{0.47-0.61}); this difference was statistically significant (p-value &amp;lt;0.05). When we evaluated the age adjusted incidence rate in each age group by different race-ethnicities, Hispanics had a statistically significant higher incidence in each age group except in 80+ yrs age group. About 52% of population died during the study period from any cause. We limited our survival analysis to patients without second malignancy to avoid the confounding effect of another cancer associated mortality. We evaluated OS differences between race-ethnicity in a multivariate model that adjusted for age, sex and income. We found that when compared to NHW, Hispanics (Hazard Ratio (HR) 1.3{1.16-1.46}; p&amp;lt;0.01) and NHB (HR 1.24{1.03-1.5};p 0.02) had worse overall survival. We also showed increased mortality in older than younger adults with B-ALL (Table 2), in line with prior knowledge. There was slightly decreased OS seen in males compared to females, and the difference barely reached statistical significance (HR 0.91{0.83-1.0}; p 0.05). Patients from the poorest counties had worse survival than those in counties with higher median income (Table 2). Conclusion: Our study showed a significant survival disparity in adult B-ALL by race and ethnicity in the modern era. This can partly be attributed to differences in access to care as shown in our study. Interestingly, Hispanic and NHB have a significantly worse overall survival compared to NHW and NHAPI even after accounting for income differences, as a surrogate for access to care. This could be due to other unaccounted measure of health disparity, availability of allogeneic transplantation and/or difference in disease biology. Further studies are needed to evaluate such differences, identify barriers to care in minority populations and characterize potential differences in the genetic make-up of B-ALL in the various ethnic/racial groups. Disclosures Sica: Physician's Education Resources (PER): Honoraria. Verma:Stelexis: Equity Ownership, Honoraria; Acceleron: Honoraria; Celgene: Honoraria; BMS: Research Funding; Janssen: Research Funding.

Detection of minimal residual disease in childhood B-acute lymphoblastic leukemia by 4-color flowcytometry

Monitoring of minimal residual disease (MRD) is currently considered the most powerful predictor of outcome in acute lymphoblastic leukemia (ALL). Achievement of a negative MRD state assessed by multicolor flowcytometry (MFC) is an important predictor of disease-free survival (DFS) and overall survival (OS) in ALL patients. We sought to determine whether panels of antibodies combination are more suitable for detection of MRD in Childhood ALL. Eighty-four (84) patients with ALL (B-lineage subtype) were enrolled in this study. Normal template for B cell precursors was established in 15 controlparticipants using 4-four panels of monoclonal Antibodies (Mo Abs),{CD22, CD45, CD58 and CD97 in combination with CD10, CD19, CD34}. At diagnosis, CD22 exhibited the lowest incidence of expression in only 50% of all patients, while CD45, CD58, and CD97 were expressed in 80.9, 59.5 and 92.8%, respectively. Analysis of MRD was performed for each Mo Abs combination at day 0 and day 14 post-induction of chemotherapy by 4-color (FCM). The incidence of MRD was 61.9, 70.6, 60.0 and 55.1% for CD22, CD45, CD58 and CD97, respectively. In B-ALL patients, (CD10/CD19/CD34/CD45)+(CD10/CD19/CD34/CD97) represented the highest incidence of expression of leukemic cells markers with a significant correlation with blasts count, suggesting that these are more specific for MRD detection. Also FCM is relatively cost effective for detection of MRD in ALL patients and its applicability in routine leukemia lab is valuable. MRD evaluation at the end of the induction therapy (i.e. day 35 or 42 according to the different schedules) is advised. Also, Ig/T cell receptor gene rearrangements and gene fusions analyzed by polymerase chain reaction (PCR) are preferred.

Meta-analysis of gene expression in relapsed childhood B-acute lymphoblastic leukemia

BackgroundRelapsed pediatric B-acute lymphoblastic leukemia (B-ALL) remains as the leading cause of cancer death among children. Other than stem cell transplantation and intensified chemotherapy, no other improved treatment strategies have been approved clinically. Gene expression profiling represents a powerful approach to identify potential biomarkers and new therapeutic targets for various diseases including leukemias. However, inadequate sample size in many individual experiments has failed to provide adequate study power to yield translatable findings. With the hope of getting new insights into the biological mechanisms underpinning relapsed ALL and identifying more promising biomarkers or therapeutic targets, we conducted a meta-analysis of gene expression studies involving ALL from 3 separate studies.MethodBy using the keywords “acute lymphoblastic leukemia”, and “microarray”, a total of 280 and 275 microarray datasets were found listed in Gene Expression Omnibus database GEO and ArrayExpress database respectively. Further manual inspection found that only three studies (GSE18497, GSE28460, GSE3910) were focused on gene expression profiling of paired diagnosis-relapsed pediatric B-ALL. These three datasets which comprised of a total of 108 matched diagnosis-relapsed pediatric B-ALL samples were then included for this meta-analysis using RankProd approach.ResultsOur analysis identified a total of 1795 upregulated probes which corresponded to 1527 genes (pfp < 0.01; FC > 1), and 1493 downregulated probes which corresponded to 1214 genes (pfp < 0.01; FC < 1) respectively. S100A8 appeared as the top most overexpressed gene (pfp < 0.01, FC = 1.8) and is a potential target for further validation. Based on gene ontology biological process annotation, the upregulated genes were most enriched in cell cycle processes (enrichment score = 15.3), whilst the downregulated genes were clustered in transcription regulation (enrichment score = 12.6). Elevated expression of cell cycle regulators (e.g kinesins, AURKA, CDKs) was the key genetic defect implicated in relapsed ALL, and serve as attractive targets for therapeutic intervention.ConclusionWe identified S100A8 as the most overexpressed gene, and the cell cycle pathway as the most promising biomarker and therapeutic target for relapsed childhood B-ALL. The validity of the results warrants further investigation.

Detection of Minimal Residual Disease in Childhood B-Acute Lymphoblastic Leukemia by 4-Color Flow Cytometry

Monitoring of minimal residual disease (MRD) is today considered the most powerful predictor of outcome in acute leukemias, including acute lymphoblastic leukemia (ALL). The study aimed to determine whether panel of antibodies combination are more suitable than others for detection of MRD in Childhood B-lineage ALL. Eighty four (84) patients of ALL (B-lineage subtype) were enrolled in this study. Normal template for B. Cell precursors were been established in 15 control Patients by using 4 panels of monoclonal Abs (Mo Abs), {CD22, CD45, CD58 and CD97 in combination with CD10, CD19, CD34}. At diagnosis CD22 having the lowest incidence expression between the patients in 50% only, but CD45, CD58, and CD97 were expressed in 80.9%, 52.3% and 92.8% respectively. Analysis of MRD was performed for each Mo Abs combination at day 0 and day 14 post induction of chemotherapy by 4-color flow cytometer (FCM). The incidence of MRD were 61.9%, 70.6%, 60.0% and 55.5% for CD22,CD45,CD58 and CD97 respectively. Seventy-six from total 84 cases studied (90.0%) had at least one LAIP. Of these, 22 (29.0%) had only one LAIP and 54 cases (71.0%) had ≥ 2 LAIPS Conclusion: In the B-ALL patients (CD10/CD19/CD34/CD45)+ and (CD10/CD19/CD34/CD97)+, represented the highest incidence markers expression of leukemic cells with a significant correlation with blasts count, so it's the more specific for MRD detection.

Abstract 1297: CDK4/CDK6 inhibition in childhood B-acute lymphoblastic leukemia: a new strategy to mediate glucocorticoid sensitivity

Abstract Unrestrained cell proliferation and cell cycle deregulation are common features in almost all human cancers. Among the CDKs that tightly control cell cycle progression, cyclin D-dependent kinases, CDK4 and CDK6 are considered important oncogenic drivers in many cancers. Although many reports successfully described CDK4/CDK6 inhibitors against a broad range of carcinomas, few studies have been performed on leukemia. Deletion and methylation of CDK4/CDK6 inhibitor CDKN2A, are frequently observed in B-acute lymphoblastic leukemia (B-ALL) and gene expression analysis performed in a cohort of childhood patients showed that cyclin D1, CDK4 and CDK6 are highly expressed. Moreover, Reverse Phase Protein Arrays (RPPA) analysis showed that cyclin D1 expression is higher in High Risk-MRD patients. These results suggest specific inhibition of cyclin D/CDK4/CDK6 axis as an attractive strategy to improve the effects of standard chemotherapy on B-ALL patients. The aim of this study was to evaluate the effect of dual inhibition of CDK4/CDK6 in B-ALL. To this purpose we treated two B-ALL dexamethasone resistant cell lines, SEM and RCH-ACV, and two B-ALL dexamethasone sensitive cell lines, RS4;11 and NALM6, with ribociclib, a highly specific CDK4/6 inhibitor. As expected, treatment with ribociclib induced a strong cell cycle arrest in G1 phase in a time-dose dependent manner along with a dose-dependent decrease in phosphorylated Rb and increase of the expression of cell cycle inhibitors p21 and p27. Moreover, a strong dose-dependent reduction of clonogenic potential was observed in SEM cell line, by CFU assay. No significant reduction in cell viability was observed. However, ribociclib exposure strongly synergized (CI&amp;lt;1) with dexamethasone in SEM and RCH-ACV resistant cell lines with a strong decrease of proliferation and a significant increase of apoptotic cell death. Immunoblot analysis showed a decrease in phosphorylated Rb, the activation of caspase-9 and the cleavage of the effector caspase-3 starting from 48 h of co-treatment, in agreement with the appearance of annexin-V positive cells. The synergistic effect of ribociclib-dexamethasone combination was confirmed on primary cultures derived from pediatric patients affected by B-ALL. We are actually investigating on the mechanism of this synergistic activity, and the effect of CDK4, CDK6 and cyclin D1 silencing will be presented. Preliminary experiments show a modest increase in glucocorticoid receptor expression after ribociclib treatment or CDK6 silencing in RCH-ACV cells. Our findings support the concept that pharmacologic inhibition of CDK4/CDK6 may represent a useful therapeutic strategy to control cell proliferation in B-ALL and provide new insight in understanding potential mechanisms of glucocorticoid resistance. Citation Format: Roberta Bortolozzi, Elena Mattiuzzo, Elena Mariotto, Benedetta Accordi, Luca Trentin, Giuseppe Basso, Giampietro Viola. CDK4/CDK6 inhibition in childhood B-acute lymphoblastic leukemia: a new strategy to mediate glucocorticoid sensitivity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1297.

Molecular analysis of childhood B-acute lymphoblastic leukemia: Identification and prognosis of rare breakpoints

Molecular analysis of childhood B-acute lymphoblastic leukemia: Identification and prognosis of rare breakpoints

Heterogeneity of Abnormal RUNX1 Leading to Clinicopathologic Variations in Childhood B-Lymphoblastic Leukemia.

Abnormalities of the RUNX1 gene in childhood B-acute lymphoblastic leukemia (B-ALL) are manifested by ETV6-RUNX1 or RUNX1 amplification. A detailed comparison between the two regarding clinicopathologic features with genetic analysis has not been performed previously. This parallel study assessed how different RUNX1 abnormalities affect the clinicopathology of B-ALL. We compared clinicopathologic factors, including age, sex, WBC count, cerebrospinal fluid (CSF) involvement, immunophenotype, and blast proliferation rate between B-ALL with RUNX1 amplification (10 cases) and B-ALL with ETV6-RUNX1 translocation (67 cases) in childhood B-ALL. CD7 was often expressed in RUNX1 amplification but not in ETV6-RUNX1 (44% vs 0%, P = .0001) and appeared to correlate with CSF involvement in the former group (3/4 [75%]). CD13 was often detected in ETV6-RUNX1 with additional RUNX1 gain (38%) with an even higher frequency in double ETV6-RUNX1 translocation (77%), but was not detected in RUNX1 amplification (0%, P < .05). Children with RUNX1 amplification were older and more often CSF positive, while those with ETV6-RUNX1 were younger, more frequently had hyperleukocytosis, and had higher blast proliferation rates. RUNX1 copy numbers seem to be proportional to the age of B-ALL onset and the frequency of CSF involvement, while RUNX1 amplification vs translocation causes aberrant expression of CD7 and CD13, respectively.

Molecular analysis of childhood B-acute lymphoblastic leukemia: Identification and prognosis of rare breakpoints

Acute lymphoblastic leukaemia (ALL) is the most common subtype of childhood cancer. Detection of a specific gene rearrangement allows the identification of prognostically relevant subgroups in childhood B-ALL. There are four common gene rearrangements which are widely studied to see prognostical values (TEL-AML1, BCR-ABL, E2A-PBX1, MLL-AF4) in childhood B-ALL. In this study we show the prevalence of these common gene rearrangements and also explain the way to identify some rare breakpoints which also occur in these gene rearrangements. 97 samples received for diagnosis from paediatric B-ALL patients were included in this study. Qualitative reverse transcriptase PCR was used for detection of the TEL-AML1-t(12;21), E2A-PBX1-t(1;19), BCR-ABL1-t(9;22) and MLL-AF4 t(4;11) fusion transcripts. Unusually sized amplicons were confirmed by FISH and DNA sequencing to confirm atypical breakpoints. Amongst the paediatric B-ALL samples t(12;21), was detected in (∼20%), t(9;22), was detected in (∼8%), t(1;19) was detected in (∼9%) and t(4;11) was detected in 2 cases. t(12;21) with intron 1of the AML1 gene was detected as the most common gene rearrangement in paediatric ALL, whereas one rare form of the TEL-AML1 breakpoint in which TEL is fused with intron 2 of AML1 was also observed. In the t(9;22) breakpoints e13a2, e14a2 and e1a2 were detected as the common breakpoints. Two atypical and rare breakpoint of t(9;22) were detected namely e6a2 and e13a3 in paediatric ALL. TEL-AML1 was found to be the most common translocation in Paediatric B-ALL. Identification of the rare breakpoints through RT-PCR technique requires designing of PCR in such a way that it can detect these rare breakpoints also.

Childhood B-acute lymphoblastic leukemia: a genetic update.

In the pediatric population, B-acute lymphoblastic leukemia (B-ALL) is the most prevalent childhood hematological malignancy, as well as the leading cause of childhood cancer-related mortality. Advances in cytogenetics utilizing array-based technologies and next-generation sequencing (NGS) techniques have revealed exciting insights into the genetic basis of this disease, with the hopes of developing individualized treatment plans for affected children. In this comprehensive review, we discuss our current understanding of childhood (pediatric) B-ALL and highlight the most recent genetic advances and their therapeutic implications.