Peripheral Blood Blast Percentage Research Articles

Comparison of the 2022 world health organization classification and international consensus classification in myelodysplastic syndromes/neoplasms

In 2022, two novel classification systems for myelodysplastic syndromes/neoplasms (MDS) have been proposed: the International Consensus Classification (ICC) and the 2022 World Health Organization (WHO-2022) classification. These two contemporary systems exhibit numerous shared features but also diverge significantly in terminology and the definition of new entities. Thus, we retrospectively validated the ICC and WHO-2022 classification and found that both systems promoted efficient segregation of this heterogeneous disease. After examining the distinction between the two systems, we showed that a peripheral blood blast percentage ≥ 5% indicates adverse survival. Identifying MDS/acute myeloid leukemia with MDS-related gene mutations or cytogenetic abnormalities helps differentiate survival outcomes. In MDS, not otherwise specified patients, those diagnosed with hypoplastic MDS and single lineage dysplasia displayed a trend of superior survival compared to other low-risk MDS patients. Furthermore, the impact of bone marrow fibrosis on survival was less pronounced within the ICC framework. Allogeneic transplantation appears to improve outcomes for patients diagnosed with MDS with excess blasts in the ICC. Therefore, we proposed an integrated system that may lead to the accurate diagnosis and advancement of future research for MDS. Prospective studies are warranted to validate this refined classification.

Kinome expression profiling improves risk stratification and therapeutic targeting in myelodysplastic syndromes

AbstractThe human kinome, which comprises >500 kinases, plays a critical role in regulating numerous essential cellular functions. Although the dysregulation of kinases has been observed in various human cancers, the characterization and clinical implications of kinase expressions in myelodysplastic syndromes (MDS) have not been systematically investigated. In this study, we evaluated the kinome expression profiles of 341 adult patients with primary MDS and identified 7 kinases (PTK7, KIT, MAST4, NTRK1, PAK6, CAMK1D, and PRKCZ) whose expression levels were highly predictive of compromised patient survival. We then constructed the kinase stratification score (KISS) by combining the weighted expressions of the 7 kinases and validated its prognostic significance in 2 external MDS cohorts. A higher KISS was associated with older age, higher peripheral blood and marrow blast percentages, higher Revised International Prognostic Scoring System (IPSS-R) risks, complex karyotype, and mutations in several adverse-risk genes in MDS, such as ASXL1, EZH2, NPM1, RUNX1, STAG2, and TP53. Multivariate analysis confirmed that a higher KISS was an independent unfavorable risk factor in MDS. Mechanistically, the KISS-high patients were enriched for genesets associated with hematopoietic and leukemic stem cell signatures. By investigating the Genomics of Drug Sensitivity in Cancer database, we identified axitinib and taselisib as candidate compounds that could potentially target the KISS-high myeloblasts. Altogether, our findings suggest that KISS holds the potential to improve the current prognostic scheme of MDS and inform novel therapeutic opportunities.

Transplantation of hematopoietic progenitors in myelofibrosis.

The objective of this work is to generate recommendations on the management of allogeneic stem cell transplantation (allo-SCT) in primary myelofibrosis (PMF). A comprehensive systematic review of articles published between 1999 and 2015 (January) was used as a source of scientific evidence. The recommendations were produced through a Delphi process involving a panel of 23 experts appointed by the European LeukemiaNet and the European Blood and Marrow Transplantation Group. Key questions included patient selection, donor selection, pre-transplant management, conditioning regimen, post-transplant management, prevention, and management of post-transplant relapse. Patients with intermediate-2 or high-risk disease and age < 70 years should be considered candidates for allo-SCT. Patients with intermediate-risk 1 disease and age < 65 years should be considered candidates if they have refractory transfusion-dependent anemia, or a peripheral blood (PB) blast percentage > 2%, or adverse cytogenetics. Splenectomy before transplantation must be decided on a case-by-case basis. Patients with intermediate-2 or high-risk disease who lack a human leukocyte antigen (HLA)-matched sibling or unrelated donor should be enrolled in a protocol that uses HLA non-identical donors. PB was considered the most appropriate source of hematopoietic stem cells for transplants from HLA-matched unrelated donors and siblings. The optimal intensity of the conditioning regimen has yet to be defined. Strategies such as discontinuation of immunosuppressive drugs, infusion of donor lymphocytes, or both were considered adequate to prevent clinical relapse. In conclusion, we provide consensus-based recommendations aimed at optimizing allo-SCT in PMF. Unmet clinical needs were highlighted.

Estimation of plasma growth differentiation factor 15 level in de novo acute myeloid leukemia patients

Abstract: BACKGROUND: Acute myeloid leukemia (AML) is a diversified disorder, characterized by clonal proliferation of myeloid precursors in peripheral blood (PB) and bone marrow (BM). Growth differentiation factor 15 (GDF15) is a member of transforming growth factor-β superfamily that has an important role in cancer prognosis and pathophysiology and it can induce apoptosis and inhibit growth and invasion of tumor. OBJECTIVES: The aim of this study was to estimate the GDF15 plasma levels in patients with de novo AML and their association with patients’ survival. MATERIALS AND METHODS: A cross-section samples from 60 adult patients who were newly diagnosed with de novo AML from September 2022 to September 2023 were included. Other 30 healthy adult individuals were involved as controls. The measurement of plasma GDF15 level was established by the ELISA technique using the human GDF15 ELISA kit. RESULTS: Plasma (GDF15) was higher in AML patients, and it was associated with inferior overall survival (OS). Plasma (GDF15) level shows positive correlation with age, hemoglobin level, and insignificant correlation with the BM and PB blast percentages, total white blood cell count, sex, and platelets. CONCLUSIONS: Plasma GDF15 levels in AML patients were high at the diagnosis and were associated with inferior OS.

Changes in White Blood Cell Counts Early during Treatment of Acute Leukemia Using Differentiating Chemotherapies

Background: Differentiation syndrome (DS) is a life-threatening complication that can occur with a number of therapies used for the treatment of acute myeloid leukemia (AML). It is best characterized in patients treated with All-trans retinoic acid (ATRA) and Arsenic for acute promyelocytic leukemia (APL), or for patients receiving an IDH inhibitor for IDH1/2 mutant AML, but can also be seen with other therapies such as with FLT3 inhibitors, and in novel therapies under development such as menin inhibitors. It is critical to identify DS early, as corticosteroids can mitigate complications. The diagnosis of DS is made by recognizing a constellation of symptoms, typically including a rising white blood cell count, peripheral edema, rash, shortness of breath, pulmonary edema, and fevers. We evaluated white blood cell (WBC) count changes during treatment according to whether patients DS or not on chemotherapy. Methods: We identified adult patients who received ATRA+Arsenic for newly diagnosed APL, as well as patients with AML harboring a mutation in IDH1 or IDH2 who were treated with monotherapy IDH inhibitors (enasidenib or ivosidenib) at any point during their treatment for active AML and treated at MGH. Patients were treated at MGH between 2015 and 2023. Patients were 18 or older and had a confirmed pathological diagnosis. We interrogated the medical record to identify patients with clinical documentation of DS during treatment, as well as the treatments used for management and clinical complications. Descriptive statistics were used to identify differences in median WBC counts between patients with DS and those without DS, and comparisons were made using Wilcoxon or chi square testing as appropriate. Results: We identified 33 patients with APL who received ATRA+Arsenic, and 35 patients with AML harboring an IDH1/2 mutation treated with monotherapy IDH inhibition. Our analysis revealed that 26% (18/68) of patients had clinical documentation of differentiation syndrome, including 21% (14/33) of patients treated with ATRA+Arsenic and 11% (4/35) of patients on IDH inhibitors. In APL, the median day of a recorded diagnosis of DS was 4 days after treatment start (range 1-14 days). Patients with APL who developed DS had a higher initial WBC at treatment start compared to those who did not develop DS (6.7 vs 1.05 K/uL, p=0.03). There was no difference in hemoglobin, platelets, ANC, and percentage of peripheral blood blasts (Table 1). The WBC in DS patients started rising during the first week of treatment and peaked on Day 15 (Figure 1). Regarding treatment approaches for DS, the majority of patients were treated with steroids, (78%, 11/14) while 43% (6/14) received cytoreduction, most commonly with gemtuzumab. In IDH-mutant AML, the median day of a recorded diagnosis of DS was 35 days after treatment start (range 16-69 days). Patients with IDH-mutated AML on IDH Inhibitor monotherapy who experienced DS had a similar finding of an early temporal rise in WBC to those with APL on ATRA+Arsenic, although this rise started on day 12 and peaked on day 16 of monotherapy. Of note, these peaks occurred prior to the documentation of a clinical DS diagnosis. In contrast to APL, patients with IDH-mutant AML who developed DS had a lower baseline ANC (p=0.03) and higher percentage of peripheral blasts circulating than those without DS (p=0.03). All patients with IDH inhibitor associated DS received dexamethasone. Discussion: Patients with DS during treatment for APL on ATRA+Arsenic, as well as patients with DS with IDHmut AML on IDH inhibitors, had similar early peaks in the WBC count, occurring around 2 weeks from the start of treatment. In this small group, the IDHmut AML showed a rise in WBC that preceded the actual DS diagnosis. Understanding the timing of and risk factors for DS may help to identify at risk patients early for mitigation strategies.

Multi-Hit TP53 Mutations in Myeloid Neoplasms: Prognostic Impact of Morphologic Subtype Designation and Variant Allele Frequency

Background: Biallelic TP53 alterations result from either sequence variations or deletions involving TP53 and are not necessarily synonymous with “multi-hit TP53”. According to the 2022 international consensus classification (ICC) for myeloid neoplasms (MN), multi-hit TP53 signifies i) the presence of two or more distinct TP53 mutations, each with variant allele frequency (VAF) ≥10%, ii) a single TP53 mutation with VAF ≥50%, or iii) a single TP53 mutation with VAF ≥10% accompanied by a cytogenetically-apparent del(17p13.1), copy-neutral loss of heterozygosity (LOH) at the 17p TP53 locus, or, in the absence of LOH information, complex karyotype ( Arber et al. Blood 2022;140: 1200). The current study is focused on MN with multi-hit TP53 and examines the additional prognostic impact of morphologic subtype designation, bone marrow (BM) or peripheral blood (PB) blast percentage, TP53 VAF, and MN with diagnostic qualifiers (i.e., therapy-related, or secondary progressing from myelodysplastic/myeloproliferative/overlap syndromes/neoplasms). Methods : The current study was conducted under an institutional review board approved minimum risk protocol that allowed retrospective collection and analysis of data from Mayo Clinic patient records. Multi-hit TP53 was defined as per ICC criteria as outlined above ( Arber et al. Blood 2022;140: 1200). Morphologic subtype designations of MN were according to ICC criteria and assigned at the time of TP53 detection. NGS and cytogenetic information was available in all study patients. Survival analyses were calculated from time of TP53 mutation detection. Conventional statistical methods were applied using JMP Pro 16.0.0 software (SAS Institute, Cary, NC, USA). Results : Initial screening flagged 143 patients with biallelic TP53 abnormalities derived from formal laboratory reports of NGS data and cytogenetic studies; of these, 130 met ICC criteria for multi-hit TP53: pure erythroid leukemia (PEL; N=24), acute myeloid leukemia (AML)-not PEL (N=54), myelodysplastic syndromes (MDS; N=36), MDS/AML (N=11), and other MN (N=5). Of these 130 informative cases, 128 (98%) harbored complex/monosomal karyotype (CK/MK). Further analysis excluded patients with “other” MN (N=5) and those without CK/MK (N=2), the latter to mitigate the confounding effect of CK/MK on survival and the former because of small sample size and disease heterogeneity. Clinical and laboratory characteristics of the 124 study patients are outlined in table 1. Survival analysis stratified by ICC-defined MN subtypes revealed the prognostic relevance of morphological distinction between PEL vs “AML-not PEL” (p&amp;lt;0.01; HR 2.4) and PEL vs “ TP53-muated MDS/AML” (p=0.02; HR 2.3) while survival was similar between “AML-not PEL” and “ TP53-mutated MDS/AML” (p=0.9; Figure 1a). Survival in “ TP53-mutated MDS” was significantly longer, compared to PEL (p&amp;lt;0.01; HR 0.2), “ TP53-mutated AML-not PEL” (p=0.01; HR 0.5), and “ TP53-mutated MDS/AML” (p=0.07; HR 0.5), the latter with borderline significance (Figure 1a). Multivariable analysis confirmed the independent prognostic relevance of ICC subtype designation (p&amp;lt;0.01) and also revealed additional negative prognostic contribution from advanced age (p=0.02), male gender (p=0.02), MN, secondary (p&amp;lt;0.01), MN, therapy-related (p=0.03), and DNMT3A mutation (p=0.02). Significance was retained in all instances, with the exception of MN, therapy-related (p=0.15), when analysis was repeated after excluding PEL cases (Figure 1b). Conclusions : The current study confirms the prognostic validity of the ICC morphologic subtype designation and TP53 VAF classification threshold, in the context of multi-hit TP53. The study also highlights the prognostic distinction between PEL and “ TP53-mutated AML-not PEL” and the prognostic alignment between the latter and “ TP53-muated MDS/AML”, both of which displayed inferior survival, compared to “ TP53-mutated MDS”. The study also suggests additional prognostic contribution from secondary and therapy-related qualification while the observation regarding DNMT3A mutation requires validation with higher number of informative cases.

T-regulatory Cells in Acute Leukemia and their Relation with Induction Outcome

Abstract Background: The leukemic microenvironment has become an area of interest for researchers in recent times. Nonmalignant T and B lymphocytes form a significant part of leukemic microenvironment and are postulated to have an effect on its progression and behavior. These lymphocytes are constantly interacting with blasts and are actively involved in innate and acquired immune responses against these blasts. We decided to look at the role of T-regulatory lymphocytes in tumor surveillance and treatment outcome. Aim and Objectives: The aims and objectives of the study are to evaluate the role of T-regulatory lymphocytes in acute leukemia cases and its correlation with treatment outcome. Materials and Methods: We evaluated consecutive 55 acute leukemia cases to investigate the prognostic effect of T-regulatory cells (T-regs) in acute leukemia. The study period was between January 2021 and December 2021. All patients whose complete records were available till the completion of induction were included in the study. The immunophenotype used to characterize and evaluate T-regs was CD4+CD25+ T lymphocytes. For comparison, a total of 10 healthy controls were included in the study. Clinicohematological parameters including fever, lymphadenopathy, hepatosplenomegaly, extramedullary involvement, day 1 total leukocyte count, and blast percentage in peripheral blood and bone marrow were studied and documented to establish any possible correlation with T-regs percentage and treatment outcome. The treatment outcome evaluated in the study was complete remission postfirst induction. Results: As compared to those of healthy participants, the frequencies of CD4+CD25+ T-regs in the peripheral blood of acute leukemia patients were significantly increased (1.5% [range: 0.50%–4.3%] vs. 0.58% [range: 0.40%–1.05%], P = 0.0001). Furthermore, the frequencies of CD4+CD25+ T-regs in the peripheral blood of acute leukemia patients who did not achieve remission were significantly increased as compared to those who achieved remission (2.9% [range: 0.20%–4.3%] vs. 1.3% [range: 0.30%–2.9%], P = 0.002). No significant correlation was noted in the T-reg cells and parameters such as fever, lymphadenopathy, hepatosplenomegaly, extramedullary involvement, day 1 total leukocyte count, and blast percentage. Conclusion: This study suggests the possibility of using T-regs percentages as a prognostic indicator of acute leukemia and possible role of anti-T-regulatory immunomodulators in improving the outcome of disease.

Features of the TCR repertoire associate with patients' clinical and molecular characteristics in acute myeloid leukemia.

Allogeneic hematopoietic stem cell transplant remains the most effective strategy for patients with high-risk acute myeloid leukemia (AML). Leukemia-specific neoantigens presented by the major histocompatibility complexes (MHCs) are recognized by the T cell receptors (TCR) triggering the graft-versus-leukemia effect. A unique TCR signature is generated by a complex V(D)J rearrangement process to form TCR capable of binding to the peptide-MHC. The generated TCR repertoire undergoes dynamic changes with disease progression and treatment. Here we applied two different computational tools (TRUST4 and MIXCR) to extract the TCR sequences from RNA-seq data from The Cancer Genome Atlas (TCGA) and examine the association between features of the TCR repertoire in adult patients with AML and their clinical and molecular characteristics. We found that only ~30% of identified TCR CDR3s were shared by the two computational tools. Yet, patterns of TCR associations with patients' clinical and molecular characteristics based on data obtained from either tool were similar. The numbers of unique TCR clones were highly correlated with patients' white blood cell counts, bone marrow blast percentage, and peripheral blood blast percentage. Multivariable regressions of TCRA and TCRB median normalized number of unique clones with mutational status of AML patients using TRUST4 showed significant association of TCRA or TCRB with WT1 mutations, WBC count, %BM blast, and sex (adjusted in TCRB model). We observed a correlation between TCRA/B number of unique clones and the expression of T cells inhibitory signal genes (TIGIT, LAG3, CTLA-4) and foxp3, but not IL2RA, CD69 and TNFRSF9 suggestive of exhausted T cell phenotypes in AML. Benchmarking of computational tools is needed to increase the accuracy of the identified clones. The utilization of RNA-seq data enables identification of highly abundant TCRs and correlating these clones with patients' clinical and molecular characteristics. This study further supports the value of high-resolution TCR-Seq analyses to characterize the TCR repertoire in patients.

Abstract 6547: Features of the TCR repertoire associate with patient’s clinical and molecular characteristics in acute myeloid leukemia

Abstract Allogeneic hematopoietic stem cell transplant (allo-HSCT) remains the most effective strategy for high risk patients with acute myeloid leukemia (AML). Leukemia specific neoantigens when presented by the major histocompatibility complexes (MHCs) are recognized by the T cell receptors (TCR) triggering the graft versus leukemia effect. Unique TCR signature is generated by a complex rearrangement process of an array of variable (V), diversity (D), and joining (J) exons to form a functional receptor with complementary determining regions 3 responsible for the interaction between the TCR and the peptide-MHC. The generated TCR repertoire undergoes dynamic changes with the onset and progression of leukemia and with the course of treatment. To better understand how the TCR repertoire impacts disease progression and patient’s clinical outcome, we leveraged RNA-seq data from The Cancer Genome Atlas (TCGA) to extract the TCR sequences using TRUST4 and MIXCR and examined the association between features of the TCR repertoire in patients with AML and their clinical and molecular characteristics. Data were analyzed by normalizing the number of unique clones to the number of total RNA-seq reads specific for each sample and one minus peripheral blood blast percentage. Both TRUST4 and MIXCR data showed a strong correlation between the number of unique clones for TCRA and TCRB per patient (r=0.944, p &amp;lt;0.001 for TRUST4, r=0.941, p &amp;lt;0.001 for MIXCR). Only 1389 TCRA clones (28.9%; TRUST4: 3450, MIXCR: 2747) and 1327 TCRB (31.3%; TRUST4: 3986, MIXCR: 1584) unique clonotypes were shared by the two computational tools. Nevertheless, we were able to identify the majority of the known TRAV and TRBV segments. Our analysis shows that the normalized number of unique TCRA and TCRB clones were lower in patients carrying FLT3 mutations (TRUST4: TCRA: p=0.013; TCRB: p=0.058; MIXCR: TCRA: p=0.043; TCRB: p=0.030), and higher in patients carrying IDH1 mutations (TRUST4: TCRA: p=0.037; TCRB: p=0.038; MIXCR: TCRA: p=0.037; TCRB: p=0.002) compared with patients carrying the wild type gene. No significant difference was observed for DNMT3A, NPM1, TET2, RUNX1, CEBPA IDH2, NRAS, WT1 and TP53 compared with wild type. Although the normalized number of unique TCR clones was not significantly associated with patient’s overall survival, we found that patients that shared more than five TCRB clones with other patients had an improved overall survival compared with patients that shared less than 5 clones (median OS: 55.4 vs 17 months, p=0.058). Despite the limitations of low TCR gene coverage associated with RNAseq data and the small sample size, we were able to find associations between TCR repertoire and clinical and molecular features in patients with AML using two different computational tools. This study further supports the need for TCR-Seq analyses to provide the depth needed to characterize the TCR repertoire in patients with AML. Citation Format: Mateusz Pospiech, Mukund Tamizharasan, Yu-Chun Wei, Advaith M. Kumar, Mimi Lou, Joshua Milstein, Houda Alachkar. Features of the TCR repertoire associate with patient’s clinical and molecular characteristics in acute myeloid leukemia. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6547.

Lncrna Famlf-2 Inhibits Acute Lymphoblastic Leukemia Apoptosis through the p38 MAPK Signaling Pathway

Background:Acute lymphocytic leukemia (ALL) is a hematologic malignancy caused by the clonal proliferation of immature lymphocytes. Long noncoding RNAs (lncRNAs) are involved in the pathogenesis and progression of ALL. Our previous study identified Familial acute myelogenous leukemia related factor (FAMLF) from a AML pedigree. There are at least three splice variants from FAMLF, referred as FAMLF-1, FAMLF-2 and FAMLF-3. We have shown higher expression of FAMLF-1 was related to a higher complete remission (CR) rate, and shorter relapse free survival (RFS) in AML. Another FAMLF variants, FAMLF-2 is highly expressed in ALL, and the potential mechanism of FAMLF-2 in regulating ALL progression is unclear. This study aims to investigate the functional and mechanistic roles of FAMLF-2 in ALL. Methods:The expression of FAMLF-2 was detected by real-time PCR (Q-PCR) in peripheral blood of ALL patients (N=85) and healthy controls (N=60). The full length of FAMLF-2 was obtained by 5' and 3' rapid amplification of the cDNA ends (RACE). FAMLF-2 subcellular location in Jurkat cells was detected by lncRNA FISH, nuclear/cytoplasmic RNA fractionation, and qPCR. The proliferation and apoptosis of Jurkat cell were determined by CCK-8 and flow cytometry experiments in vitro. RNA-seq was performed to study the molecular mechanism of FAMLF-2 in regulating ALL cell apoptosis. Results:The FAMLF-2 mRNA expression and in ALL patients was significantly higher than those in the normal individuals (P=0.000). The expression of FAMLF-2 was positively correlated with percentage of peripheral blood blasts (P=0.032). The ALL patients with higher FAMLF-2 expression had significantly poor overall survival (P=0.036). We defined a 2393-bp full-length transcript of FAMLF-2, and examined the subcellular localization of FAMLF-2, which showed that FAMLF-2 predominately resides in the nucleus of Jurkat cells. The cell proliferation was inhibited, and cell apoptosis was induced when FAMLF-2 were down-regulated in Jurkat and Nalm6 cells, whereas the overexpression of FAMLF-2 showed the opposite results. We analyzed the RNA-seq data of the knockdown and overexpression of FAMLF-2 in Jurkat cells, and the GSEA analysis suggested that FAMLF-2 knockdown was associated with "MYC TARGETS V1", "MYC TARGETS V2" pathways. The knockdown of FAMLF-2 in Jurkat cells upregulated the expression of p-P38 and downregulated the expression of c-Myc, bcl-2. Conclusion: Taken together, our study indicate that FAMLF-2 inhibits the apoptosis of ALL through the p38 MAPK signaling pathways, which might act as a prospective prognostic biological marker for ALL. Keywords: Acute lymphocytic leukemia, Long noncoding RNAs, FAMLF-2, apoptosis, p38 MAPK Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Characterization of Survival Outcomes and Clinical and Molecular Modulators in Adult Patients with Core-Binding Factor Acute Myeloid Leukemia (CBF-AML) Treated with Hidac Consolidation: An Alliance Legacy Study

Introduction CBF-AML is a specific disease entity defined by the presence of either t(8;21)(q22q22)RUNX1-RUNX1T1, or inv(16)(p13.1q22) or t(16;16)(p13.1;q22) creating the CBFB-MYH11 fusion gene, and is associated with a relatively favorable prognosis. Yet, outcomes are variable and relapse occurs in ~50% of patients (pts). Whereas several clinical and molecular features have been suggested to modulate survival, consensus data are sparse. Moreover, there is persistent controversy about the optimal dose intensity of cytarabine consolidation, which complicates interpretation of correlative studies with respect to outcome associations. Thus, we analyzed outcomes of a large cohort of CBF-AML pts treated with high-dose cytarabine (HiDAC) consolidation with respect to cytogenetic subtypes and co-existing molecular features. We analyzed clinical and molecular characteristics and outcomes of 304 pts with CBF-AML aged 18-59 years [y; inv(16)/t(16;16), n=186; t(8;21), n=118] who were similarly treated and achieved a complete remission upon standard cytarabine/anthracycline induction followed by HiDAC on frontline Cancer and Leukemia Group B/Alliance for Clinical Trials in Oncology protocols between 1986-2016. All pts had centrally reviewed cytogenetics and samples from 136 pts underwent comprehensive molecular profiling of 80 AML-associated genes for association studies. Kaplan-Meier method was used to estimate probabilities of disease-free survival (DFS) and overall survival (OS), and the log-rank test evaluated differences between survival distributions. Cox proportional hazard regression analyses was used for DFS and OS univariable and multivariable modeling. Results Thirty-eight percent of pts relapsed and 69% were alive 5y after diagnosis (median OS): 12.5y with median follow-up of 8.6y. Outcomes of t(8;21) and inv(16)/t(16;16) AML were similar; relapse rates: 35% vs 40%, 5y OS rates, 64% vs 72%, respectively. Although outcome of pts with inv(16) was not significantly different from outcome of t(16;16) pts, the latter had, by trend, a superior DFS (5y rates, 75% vs 47%, P=0.07); their OS was not significantly different (5y rates, 81% vs 64%, P=0.24). As secondary cytogenetic abnormalities are common and impact on survival has yielded controversial results, we next analyzed the impact on outcomes of our pt cohort. None of the frequently observed secondary abnormalities [i.e., loss of X or Y chromosomes, +8, or del(9q) in t(8;21) pts and +22 or +8 in inv(16)/t(16;16) pts] affected the outcomes of CBF-AML pts we analyzed, which contrasts with some previous reports. The presence of a complex karyotype also did not negatively affect the favorable survival of CBF-AML pts. Next, we assessed the impact of recurrent gene mutations on pt outcomes. While KIT mutations have previously been shown to confer inferior survival, our data suggest that presence of a KIT mutation negatively affects DFS of both t(8;21) and inv(16)/t(16;16) AML pts [5y rates, t(8;21) 36% vs 67%, P= 0.03; inv(16)/t(16;16), 21% vs 61%, P<0.001], and also OS in inv(16)/t(16;16) pts (5y rates, 52% vs 74%, P=0.04). Co-existing FLT3-TKD mutations were almost exclusively found in inv(16)/t(16;16) in 16/18 cases. Though a negative prognostic impact of FLT3-TKD has been suggested, this was not found in our cohort (5y rates, DFS, 56% vs 55%, P=0.93; OS, 78% vs 68%, P=0.69). Furthermore, neither the presence of NRAS or KRAS mutations affected survival outcomes. In multivariable analyses for OS, a higher percentage of peripheral blood blasts was the only feature associated with inferior survival [HR, 1.14 (95% CI, 1.04-1.25), P=0.004]. Conclusions Our analysis of a large cohort of younger CBF-AML pts treated on frontline protocols with 7+3-based induction therapy and HiDAC consolidation, showed though these pts are considered favorable risk, they demonstrate varying long-term survival. Clinically, the presence of high blast count at time of diagnosis, was a strong adverse prognosticator for inferior survival. With respect to recurrent co-occurring cytogenetic aberrations or gene mutations, only KIT mutations associated with inferior survival in pts with t(8;21) and in those with inv(16)/t(16;16). Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org. Clinicaltrials.gov: NCT00048958(CALGB 8461), NCT00899223(CALGB 9665), NCT00900224(CALGB 20202) *co-senior authors

Induction Related Mortality Score in Acute Myeloid Leukemia: Prospective Validation Study (pRISM) of the Hematology Cancer Consortium (HCC)

Treatment of Acute Myeloid Leukemia (AML) should be initiated at the earliest to improve outcomes. The standard induction regimen (3+7) is associated with significant risk of induction mortality, especially in resource limited settings. Hence there is a need to develop risk prediction model for our patient cohorts. Treatment related mortality (TRM) scoring systems developed and used in developed country, mostly for the elderly, may not be directly applicable to population of young adults in developing countries, many of whom have poor general condition and infections at baseline. We developed a multivariate model of induction mortality score in 2019, from a retrospective AML cohort of the Indian acute leukemia research database [INwARD] established by the Hematology Cancer Consortium (HCC). In the present study we have validated the approach and recalibrated the induction mortality score on a multicenter prospective cohort. Prospective data for adult AML, for a period of 20 months, starting July 2020 to February 2022, was received from 17 member institutions in a central online data management system. Potential variables that would predict mortality were selected based on clinical and statistical significance. Eleven variables relating to baseline patient and disease characteristics (age, ECOG performance status, duration of symptoms in days, albumin, creatinine, bilirubin, white cell count, platelet, hemoglobin, peripheral blood blast percentage, and presence of infection requiring intravenous antibiotic within one week prior of starting induction), were considered for the predictive model using machine learning (ML) algorithms: Logistic regression (LR), Support Vector Machine (SVM) and eXtreme Gradient Boosting (XGB). Of the various ML algorithms, the best model was chosen based on area under curve (AUC) from the training dataset and validity statistics from the test dataset. We also used the same approach to predict intensive care unit (ICU) admission. R software was used to analyze the data. Of the 779 treated cases during the study period, 438 received intensive induction, '3+7' being the most common regimen in 80%. The median age of this cohort was 37 years (IQR 28, 46), male to female ratio 1.2. European Leukemia Net (ELN) risk group was good in 31.3 % (n= 137), intermediate in 44% (n=192), high in 13.7% (n=60), and unknown in 11% (n=48). Complete remission was attained in 56.3%. Overall induction mortality was 13.0%, ranging from 7.1% to 40% across different centers. Infection was the most common cause of death in 52%. For predicting induction mortality using 11 covariates, SVM provided the best threshold as 0.126, with an AUC of 94.71%, sensitivity (92.50%), and specificity (96.11%). A comparison of the ML algorithms is shown in Fig 1 and statistics for the SVM model in Table 1. ICU admission was observed in 22.8%; a cut-off threshold of 0.231, with an AUC of 93.3% in the SVM model predicted ICU admission with sensitivity of 93.15% and specificity of 89.7%. Induction mortality prediction score developed in a retrospective cohort was effectively applied to contemporary prospective data from major centers across the country, with diverse resources and patient profiles. Thus, we have validated the machine learning approach of predicting induction mortality with variables relevant to regional clinical settings including baseline infection. The SVM model predicted the risk of both induction mortality as well as morbidity with high accuracy. An online calculator is being developed to help clinicians use this score in regular practice for guiding treatment intensity as per an individual patient's risk and in directing appropriate resource utilization. Further, the approach of risk-adapted induction intensity, especially for young adult AML, based on the score adjusted to center-specific prevalence of mortality rates, is under consideration for a prospective clinical trial. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Stem Cell-Derived Gene Expression Scores Predict Survival and Leukemic Transformation in Myelofibrosis

Myelofibrosis (MF) is a myeloproliferative neoplasm (MPN) with survival outcomes ranging from months to years and variable risk of transformation to acute myeloid leukemia. Allogeneic bone marrow transplantation (BMT) can be curative but is associated with high treatment-related morbidity and mortality, therefore accurate risk stratification is important to guide clinical decision making in MF. Current risk prediction models use clinical and/or genomic features but do not consider the properties of the disease-driving stem cell population. Here, we use transcriptomic variation corresponding to both intra- and inter-patient heterogeneity among MF stem cells to generate novel gene expression-based scores predictive of survival and leukemic transformation in MF. To train and validate novel prognostic scores in MF, we identified 358 patients from an MPN registry at the Princess Margaret Cancer Centre (ClinicalTrials.gov Identifier: NCT02760238) from whom peripheral blood (PB) cells were collected near the date of MF diagnosis. All patients were diagnosed with either primary, post-PV, post-ET or pre-fibrotic MF with clinical follow-up of up to 12.2 years. RNA was extracted from unsorted PB mononuclear cells and RNA sequencing (RNAseq) was performed at an average depth of 50 million reads per sample. We randomly split our MF cohort into training (70%; n=250) and test sets (30%; n=108) and utilized a repeated nested cross validation approach together with statistical regression, to generate and assess the performance of models to predict survival within the training set. We tested 36,000 models derived from 36 initial MF-related genesets, ranging from stem-cell specific genesets to the whole transcriptome. The most accurate models by cross validation (median multivariable p-value = 6e-5) were produced from our retrospective identification of highly variable genes in single-cell RNAseq data derived from 82,255 Lin-CD34+ MF stem and progenitor cells across 15 patients (Psaila et al., 2020). Thus, features of intra- and inter-patient heterogeneity among MF stem and progenitor cells proved to be the most relevant for predicting survival. From these features, we derived our final model calculated as the weighted sum of gene expression across 24 genes (termed MPN24). We categorized patients with MPN24 scores above or below the training cohort median as MPN24 high or low, respectively. This model was validated in the test set, with high and low score patients experiencing 5-year survival rates of 71% [95% CI 57-88%] and 21% [95% CI 9%-52%], respectively, when censored at time of BMT (HR = 5.3 [95% CI 2.6-10.5]; p=2.1e-6) (Figure 1A). MPN24 retained independent prognostic value in multivariable analysis incorporating age, sex, DIPSS category, ECOG status, fibrosis grade, constitutional symptoms, and PB blast percentage (adjusted HR = 5.7 [95% CI 2.2-14]; p = 3e-4). Importantly, DIPSS classification remained a significant covariate, indicating that MPN24 and DIPSS capture distinct features of disease. We therefore developed a new three-tier classification scheme integrating both DIPSS and MPN24 scores (Figure 1B). Patients classified as low-, intermediate- or high-risk in this new classification scheme experienced 5-year survival rates of 88.2% [95% CI 77.9% - 99.9%], 39.3% [95% CI 19.9% - 77.7%] and 10.8% [95% CI 2.1% - 55.8%], respectively (likelihood ratio test p = 1e-8). Finally, from the MPN24 genes we derived a 13 gene subscore (MPN13) predictive of leukemic transformation in the training set. Patients in the test set scoring above the 80th percentile from the training set were classified as high risk and the remaining as low risk. Although total leukemic samples were limiting, MPN13 was significantly associated with risk of transformation (p=4.7e-03) with low and high-risk patients experiencing 3-year cumulative incidences of transformation of 5.2% [95% CI 0.2%-10.2%] and 28.6% [95% CI 3.1%-54.0%] respectively, after adjusting for death as a competing risk. Future studies will transfer our scores to the Nanostring platform for testing in independent cohorts. In summary, we used transcriptional variation among MF stem and progenitor cells to derive novel gene expression scores predictive of survival and leukemic transformation and developed a new integrated 3-tier model for predicting risk in MF patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Prognostic Impact of Persistent Measurable Residual Disease in Patients with Acute Myeloid Leukemia FLT3+ Treated with Intensive Chemotherapy Plus Midostaurin - a Retrospective Study of the Polish Adult Leukemia Group (PALG)

Background: Measurable residual disease (MRD) is detected during morphological remission after standard chemotherapy in acute myeloid leukemia (AML) patients (pts). It is a strong prognostic factor for relapse and shorter overall survival (OS). Immunophenotyping by multiparameter flow cytometry (MFC) is currently the most commonly used method in AML pts. There is still a lack of studies evaluating MRD in specific AML populations in the era of targeted therapies, including thyrosine kinase inhibitors. A retrospective study in adult pts with a newly diagnosed AML FLT3+ treated with intensive chemotherapy plus midostaurin has been performed to evaluate the prognostic impact of positive MRD (MRD+) on RFS and OS. Objectives: To assess the prognostic impact of MRD status during the clinical course of AML FLT3+ on RFS and OS. Patients and methods: Seventy three pts with AML FLT3 were treated in Polish hematological centers between 2018 and 2021. Bone marrow aspiration was performed after induction and consolidation treatment to assess response and MRD by MFC. MRD+ was defined as ≥ 0.1% abnormal cells within mononucleated cells by MFC with diagnostic leukemia-associated immunophenotype (LAIP) and different from normal (DfN) aberrant immunophenotype approaches. Results: The median age of the pts was 55 (range: 18-74). Induction regimen was DA "3+7" in 50 (70%), DA-90 in 8 (11%), DAC in 11 (15%), other in 2 (4%) pts. Fifty seven (78%) pts achieved first composite complete remission (CRc=CR+CRi) after 1 or 2 courses of induction, 12 (17%) had primary refractory disease (PRD) and 2 (3%) pts died in aplasia. Median number of consolidation courses was 2 (range: 1-4). Fifty one (89%) pts with CR1 fulfill the criteria for MRD analysis after 1 or 2 courses of induction and 34 (48%) pts after consolidations. Thirty four pts had 2 timepoints evaluation: after induction and at the end of consolidation courses. MRD+ was reported in 35 (68%) of pts after induction (median 0.5; IQR 0.25-0.85) and in 19 (52%) of pts at the end of consolidations (median 0.64; IQR 0.22-1.99). Analysis of 4 pts groups was performed: Group 1.: MRD+ after induction and at the end of consolidations (persistent MRD+)(n=16; 47%); Group 2.: MRD+ after induction with conversion to MRD- at the end of consolidations (n=6; 18%); Group 3.: MRD- after induction with conversion to MRD+ at the end of consolidations (n=2; 6%); Group 4.: MRD- after induction and at the end of consolidations (persistent MRD-)(n=10; 29%); Baseline clinical characteristics were similar between 4 groups regarding age, FLT3-ITD and FLT3-TKD frequency, FLT3-ITD allelic ratio (AR), WBC, PLT, peripheral blood and bone marrow blast percentage, AML type: de novovs sAML vs tAML (p-values > 0.05). The probability of 1- year RFS was significantly lower in pts with persistent MRD+ (group 1.) vs group 2. vs 3. vs 4. (27% vs 83% vs 50% vs 78%; p=0.034, respectively). Relapse rate after 1 year was in group 1. vs 2. vs 3. vs 4.: 73% vs 16% vs 50% vs 20% (p=0.015), respectively. The shorter OS, but insignificant, was noted in group 1. vs 2. vs 3. vs 4. (p=0.49). A univariate analysis revealed that allo-HSCT (hazard ratio [HR] 0.345; 95% confidence interval (CI), 0.152-0.784; p=0.011) and male sex (HR, 0.433; 95% CI, 0.217-0.861; p=0.017) are predictors for longer OS. MRD- at the end of consolidations (HR, 0.211; 95% CI, 0.066-0.669; p=0.008), persistent MRD- (HR, 0.252; 95% CI, 0.070-0.909; p=0.035), allo-HSCT (HR, 0.416; 95% CI, 0.183-0.947; p=0.0368) are predictors for longer RFS. However, older age (HR, 1.049; 95% CI, 1.018-1.081; p=0.0017) and higher WBC (HR, 1.005; 95% CI, 1.002-1.008; p=0.0022) are predictors for shorter RFS. Conclusions: We observed high rate of CR1 MRD+ AML FLT3 pts after induction (68%) and at the end of consolidations (52%). Significantly lower RFS and higher relapse rate, but not OS, were noted in pts with persistent MRD+ in comparison to pts in other MRD groups. Longer follow-up period and larger studies are necessary to confirm our preliminary findings.

Frequency of CD34 and CD10 Expression in Adolescent and Young Adult Patients Having Precursor B-cell Acute Lymphoblastic Leukemia and Its Correlation With Clinical Outcomes: A Single-Center Study.

Background: The clinical outcomes of CD34 and CD10 antigens expression in adolescent and young adult (AYA) precursor B-cell acute lymphoblastic leukemia (pre-B-ALL) is not still well established. In the present study, we analyzed the laboratory characteristics and clinical outcomes of 123 AYA pre-B-ALL patients in order to evaluate the possible clinical significance of these markers.Materials and methods: In the current study clinical data of 123 consecutive AYA pre-B-ALL patients aged 18-39 years old, enrolled in adult hematology-oncology unit from December 2014 to April 2019 was analyzed. Patient clinical outcome was calculated as overall survival and disease-free survival.Results: Overall, 76.4% of patients showed CD34 expression and CD10 expression was found in 90.2%. CD34 and CD10 expression was associated with higher total leucocyte count, increased peripheral blood blast percentage, and decreased platelet count. Overall survival and disease-free survival were both significantly better in CD34 negative and CD10 negative patients compared to their CD34 positive and CD10 positive counterparts.Interpretation and conclusion: Expressions of CD34 and CD10 are adverse prognostic factors in AYA pre-B-ALL patients and the presence of these antigens influences the clinical outcome of these patients.

Spectrum of immunophenotypic aberrancies in acute leukemia along with their correlation with adverse hematological parameters

BACKGROUND: The identification of aberrant phenotypes in acute leukemia is crucial for treatment monitoring and minimal residual disease analysis. Flowcytometric immunophenotyping in acute leukemia is an important tool for the detection of these aberrancies. There is wide variation in the incidence of aberrant antigens in acute leukemia in different studies and its correlation with prognostic markers.AIMS AND OBJECTIVES: The aim and objective of this study is to assess the frequency of aberrant markers in acute leukemia and determine any association with hematological parameters.MATERIALS AND METHODS: A total of 150 newly diagnosed cases of acute leukemia during the period January 2018–December 2020 were included. The flowcytometric immunophenotyping of all the above cases was done using BD FACS Canto II.RESULTS: Out of the total 150 cases of acute leukemia, 56.7% expressed aberrant phenotype. The proportional frequency of aberrant antigen expression in B-acute lymphoid leukemia (ALL), T-ALL and acute myeloid leukemia (AML) was 56.6%, 50%, and 58.5%, respectively. CD13, CD13, and CD7 were the most common aberrancies in B-ALL, T-ALL, and AML, respectively. Aberrant myeloid phenotype in B-ALL was associated with lower mean total leukocyte count (TLC) and blast percentage in peripheral blood as compared to the B-ALL with conventional phenotypes. Aberrant lymphoid phenotype in AML was associated with a higher TLC and greater blast percentage in peripheral blood than the AML with conventional phenotypes.CONCLUSION: Aberrant lymphoid phenotype in AML is associated with unfavorable hematological features. However, aberrant myeloid phenotype in B-ALL is not associated with adverse features.

Prognostički faktori rizika za ranu smrt kod bolesnika sa akutnom mijeloidnom leukemijom

Introduction: Early death is a known complication in the treatment of patients suffering from acute myeloid leukemia (AML). It has been defined as death occurring within 28 days of the initiation of induction chemotherapy. Aim: Determining the clinical characteristics of the patient, the risk factors, the frequency, and the most common causes of early death in AML patients. Materials and methods: This retrospective study included 248 patients with diagnosed AML. At diagnosis, the following demographic and clinical-laboratory characteristics were recorded: sex, age, general functional status, i.e., performance status according to the ECOG scale, complete blood count, LDH level in the blood, percentage of blasts in peripheral blood and bone marrow, fibrinogen, PT, aPTT, D-dimer, and BMI. Patients were treated with induction and reduction chemotherapy and palliative therapy. Statistical analysis was performed using the data from the discharge summaries taken from the registers of the Clinic for Hematology of the Clinical Center of Serbia. Results: Early death occurred in 53 (21.4%) patients. The prognostic risk factors for early death were the following: age (p = 0.047), ECOG ≥ 2 (p = 0.001), leukocyte count ≥ 30 x 109 /l (p = 0.022), LDH level ≥ 450 U/l (p = 0.022), the percentage of blasts in peripheral blood (p = 0.005) and the percentage of blasts in bone marrow (p = 0.003), PT (p &lt; 0.001), as well as the ISTH score (p = 0.018). The most common cause of early death in patients aged 40 - 65 years was sepsis, while in patients older than 65 years it was respiratory failure. Conclusion: The study showed that age, the leukocyte count, the percentage of peripheral blood and bone marrow blasts, the ECOG score, LDH, PT, and the ISTH score were significant prognostic risk factors of early death in patients with AML, and that the most common cause of early death in patients aged 40 - 65 years was sepsis, while in patients older than 65 years it was respiratory failure.

FLT3 Gene Mutation in Acute Myeloid Leukemia: Correlation with Hematological, Immunophenotypic, and Cytogenetic Characteristics

Introduction In acute myeloid leukemia (AML), FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is a common driver mutation associated with high tumor burden and poor prognosis. This mutation is common in normal karyotype AML and such patients have high leukocyte count. The presence of this mutation can be predicted by certain hematological and immunophenotypic characteristics in day-to-day practice. Objective This study was undertaken to assess the strength of association between FLT3 gene mutation and hematological and immunophenotypic characteristics. Materials and Methods Morphological, hematological, immunophenotypic, and cytogenetic characteristics of FLT3 mutations recorded in 424 patients of AML in adults and children between 2016 and 2019 in a tertiary care cancer center in Western India. Blasts were classified according to French-American-British method. Tumor burden was assessed by serum lactate dehydrogenase (LDH) levels, leucocyte count, and peripheral smear blast percentage. Results Out of 424 cases, FLT3-ITD and FLT3-tyrosine kinase domain mutation were found in 72 and 25 AML patients, respectively. Patients with FLT3 mutation had high tumor burden, characterized by high leukocyte count (p &lt; 0.001), peripheral blood (p = 0.01) and bone marrow (p = 0.03) blast percentage, and high serum LDH (mean 777.8 vs. 586; p = 0.10) compared with FLT3-negative patients. They also featured high platelet count (p &lt; 0.001). Morphological, immunophenotypic, and cytogenetic characteristics also have been presented in the study. Conclusion Observations of the study suggest the presence of definitive hematological and immunophenotypic characteristics along with raised serum LDH levels serve as surrogate markers and indicators of FLT3 mutation in AML patients.

CLINICAL, CYTOGENETIC AND MOLECULAR CHARACTERIZATION OF BRAZILIAN COHORT PATIENTS WITH PRIMERY MYELOFIBROSIS AND MYELOFIBROSIS POST-POLYCYTTHEMIA VERA AND POST-ESSENTIAL THROMBOCYTHEMIA

Myelofibrosis (MF) is the most severe myeloproliferative neoplasia (MPN), with a very variable survival, which can be beyond 20 years to less than two years. The only curative treatment is allogeneic bone marrow transplantation (ABMT), but this is restricted to patients of less advanced age and is associated with significant mortality and disease relapse. Adequate prognostic characterization is essential for therapeutic decision-making, and modern prognostic indexes using molecular and cytogenetic data have been replacing the traditional indexes. Clinical and laboratory data were evaluated, bone marrow and peripheral blood karyotype were studied, and BCR-ABL1, JAK2, CALR, MPL, ASXL1, SRSF2, EZH2, IDH1, IDH2, U2AF1 mutations were investigated. The classic IPSS, DIPSS, DIPSS plus, and the most recent MIPSS70, MIPSS70 plus, MIPSS 70 plus 2.0, GIPSS, and MYSEC-PM indexes were applied to a population of 230 patients from 8 Brazilian institutions with primary myelofibrosis (MFP) and secondary myelofibrosis polycythemia vera (PV-MF) and essential thrombocythemia (TE-MF) and compared among themselves. The median-age was 65 years-old, the overall survival was 8.1 years (CI 95%, 7,2 – 10,7), with a 5 years estimated survival of 61% (53 – 70). Comparing the prognostic indexes with each other identified a greater accuracy of the prognostic indexes that use mutational and cytogenetic data on the classic prognostic indexes. In the univariate analysis, advanced age, male gender, spleen size, hemoglobin, white blood cell count, peripheral blood blast percentage, SRSF2 mutation, triple-negative patients, IPSS, DIPSS and DIPSS plus stratification, MIPSS70 high risk and MIPSS70 plus high and very high risk showed impact in survival. In the multivariate analysis, triple-negative for JAK2 V617F, CARL , and MPL (p = 0,002) and stratification by IPSS (p < 0,0001) maintained significance as risk factors for overall survival. The present study is the most extensive Brazilian cohort study of patients with MF evaluating these variables.

INCIDENCE, RISKS AND OUTCOME OF EXTRA MEDULLARY RELAPSE IN ACUTE LYMPHOBLASTIC LEUKEMIA IN CHILDREN AND ADULTS: A RETROSPECTIVE COHORT STUDY

Extra medullary relapse (EMR) is the major concern of treatment failure in acute lymphoblastic leukemia (ALL). Hence, their early detection may improve prognosis. Aim of the study is to identify risk factors and outcome of EMR patients with and without concurrent medullary relapse. We retrospectively analyzed 113 patients of ALL who presented with EMR in a tertiary cancer care hospital. Patients were divided into two groups; Group 1, combined EMR (with medullary relapse) and Group 2, isolated EMR (without medullary relapse). Clinical characteristics including total leukocyte count (TLC) &amp; peripheral blood blast percentage during presentation, phenotype, initial central nervous system (CNS) involvement and BCR-ABL translocation were analyzed to identify risk factors for EMR. Incidence of EMR in our study was 15.7% (113/720 patients). Two year incidence of combined EMR and isolated EMR was 10.1% and 5.5% respectively. CNS, followed by testis was common sites of EMR. TLC &gt;50x109/L and peripheral blood blast percentage &gt;50% at presentation was common in Group 1. BCR-ABL translocation was frequent in Group 2 and in adults compared to children (p=0.027). While Group 1 patients presented with leukocytosis (TLC &gt;10X109/L), Group 2 patients presented with leukopenia (TLC &lt;4X109 p=0.001). p=0.001).&gt;50X109/L and BCR-ABL translocation were identified as risk factors for combined EMR (p=0.004) and for in adults with isolated EMR (p=0.001) respectively.