Integrative genomic and transcriptomic profiling reveals distinct molecular subsets in adult mixed phenotype acute leukemia.

Mixed phenotype acute leukemia (MPAL) is a subtype of leukemia in which lymphoid and myeloid markers are co-expressed. Knowledge regarding the genetic features of MPAL is lacking due to its rarity and heterogeneity. Here, we applied an integrated genomic and transcriptomic approach to explore the molecular characteristics of 176 adult patients with MPAL, including 86 patients with T-lymphoid/myeloid MPAL (T/My MPAL-NOS), 42 with Ph+ MPAL, 36 with B-lymphoid/myeloid MPAL (B/My MPAL-NOS), 4 with t(v;11q23), and 8 with MPAL, NOS, rare types. Genetically, T/My MPAL-NOS was similar to B/T MPAL-NOS but differed from Ph+ MPAL and B/My MPAL-NOS. T/My MPAL-NOS exhibited higher CEBPA, DNMT3A, and NOTCH1 mutations. Ph+ MPAL demonstrated higher RUNX1 mutations. B/T MPAL-NOS showed higher NOTCH1 mutations. By integrating next-generation sequencing and RNA sequencing data of 89 MPAL patients, we defined eight molecular subgroups (G1-G8) with distinct mutational and gene expression characteristics. G1 was associated with CEBPA mutations, G2 and G3 with NOTCH1 mutations, G4 with BCL11B rearrangement and FLT3 mutations, G5 and G8 with BCR::ABL1 fusion, G6 with KMT2A rearrangement/KMT2A rearrangement-like features, and G7 with ZNF384 rearrangement/ZNF384 rearrangement-like characteristics. Subsequently, we analyzed single-cell RNA sequencing data from five patients. Groups G1, G2, G3, and G4 exhibited overexpression of hematopoietic stem cell disease-like and common myeloid progenitor disease-like signatures, G5 and G6 had high expression of granulocyte-monocyte progenitor disease-like and monocyte disease-like signatures, and G7 and G8 had common lymphoid progenitor disease-like signatures. Collectively, our findings indicate that integrative genomic and transcriptomic profiling may facilitate more precise diagnosis and develop better treatment options for MPAL.

Pattern and prognostic value of FLT3-ITD mutations in Chinese de novo adult acute myeloid leukemia.

FMS-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes in hematological malignancies. FLT3 internal tandem duplication (FLT3-ITD) mutations located in juxtamembrane domain (JMD) and tyrosine kinase domain 1 (TKD1) regions account for two-thirds of all FLT3 mutations. The outcome of patients remains unsatisfactory, with low survival rates. It is not yet known whether the different mutations within the FLT3 gene are all associated with patient outcome. In addition, the cause of FLT3-ITD in-frame duplication events remains unknown. Although there are some published studies investigating the FLT3-ITD mutation and its clinical implications in Chinese acute myeloid leukemia (AML) patients, sample sizes tend to be small and detailed molecular profiles of FLT3 mutations are lacking in these studies. In our study, 227 FLT3-ITD sequences were analyzed from 227 Chinese de novo AML patients. ITD were next classified into 3 types based on molecular profiles of insertion DNA sequences: DNA complete duplication (type I), DNA partial duplication (type II) and complete random sequence (type III). From the 154 patients, we confirmed that high ITD allelic ratio (≥.5) and allogeneic stem cell transplant treatment under CR1 are independent prognostic factors. We also presented evidence that ITD integration sites in the hinge region or beta1-sheet region are an unfavorable prognostic factor in adult AML patients with FLT3-ITD mutations. These findings may help to decipher the mechanisms of FLT3-ITD in-frame duplication events and stratify patients when considering different therapeutic combinations.

The impact of FLT3 mutations on treatment response and survival in Chinese de novo AML patients.

OBJECTIVE: Two distinct forms of FMS-like tyrosine kinase 3 (FLT3) mutations, internal tandem duplication (ITD) in the juxtamembrane domain and point mutation within the activation loop of the tyrosine kinase domain (TKD), have been identified in considerable number of patients with AML. This study was aimed to analyze the impacts of these mutations on clinical outcomes, and assess the efficacy of different therapeutic regimens (allo-HSCT, sorafenib, or conventional chemotherapy) for AML patients with FLT3 mutations after the standard induction therapy. MATERIALS AND METHODS: We analyzed DNA samples from 158 consecutive de novo AML patients (18-60 years, excluding APL) with FLT3 mutations between July 2010 and October 2015. RESULTS: We found that AML patients with FLT3-TKD mutations have more favorable clinical outcomes than those with FLT3-ITD mutations. We also found that allo-HSCT therapy subgroup achieved longer OS and RFS than non-allo-HSCT therapy subgroup for FLT3-ITD positive patients (p < 0.001, p = 0.071). However, compared with the clinical outcomes in non-primary refractory patients, sorafenib did not show an obvious beneficial effect for the primary refractory patients. Further study on a large scale is still recommended. CONCLUSIONS: FLT3-TKD-mutated AML patients have more favorable clinical outcomes than those with FLT3-ITD mutations. Allo-HSCT therapy subgroup achieved longer OS and RFS than non-allo-HSCT therapy subgroup for FLT3-ITD positive patients. Compared with the clinical outcomes in non-primary refractory patients, sorafenib did not show an obvious beneficial effect for the primary refractory patients.

[Risk Factors of Leukemia-free Survival in Ph+ ALL Patients with Allogeneic Hematopoietic Stem Cell Transplantation].

OBJECTIVE: To explore the effect of BCR-ABL gene transcripts on Leukemia-free survival (LFS) and prognosis of patients with Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The clinical data of 107 cases of Ph+ B-ALL patients received allo-HSCT from July 2006 to November 2014 in the First Affiliated Hospital of Soochow University were collected and the relationship between the clinical characteristics and LFS after transplantation was analyzed. RESULTS: Out of 107 Ph+ ALL patients (64 males and 43 females) with a median age of 30(7 to 54)years old, 35.5% (38/107) cases relapsed after transplantation within a median time of 6.9 (1.5 to 40.7) months. A total of 39 (36.4%) cases died within a median time of 19.8 (3.6 to 83.7) months after HSCT, of which 51.3% (20/39) due to disease relapse and 25.6% (10/39) due to infection. BCR-ABL gene transcripts of 49 cases turn into negative before transplantation, of which the expected 5-year cumulative incidence of relapse (CIR), non-relapse mortality (NRM) and overall survival (OS) were 26.5%, 29.5% and 41.6%, respectively. Another 49 cases still had a positive BCR-ABL gene transcripts before transplantation, of which the life expectancy of 5 year CIR, NRM and OS were 64.4%,8.9% and 48.9%, respectively. Compared with BCR-ABL positive patients, BCR-ABL negative patients showed a lower CIR (P<0.001), a higher NRM (P=0.030) and a similar OS (41.6% versus 48.9%, P=0.497). Multivariate analysis showed that BCR-ABL positive (P=0.016) and a disease statusphase ≥CR2 (P<0.001) before HSCT were independent risk factors for LFS, while the age underwent HSCT was the principal element affecting prognosis (P<0.001). CONCLUSION: Both the relapse and infection are the main causes of death in the patients after transplantation. A disease status ≥CR2 and the BCR-ABL positive before transplantation are 2 independent risk factors of LFS in the patients with Ph+ ALL after allo-HSCT.

Protective Effect of Rituximab in Chronic Graft-Versus-Host Disease Occurrence in Allogeneic Transplant patients with Epstein Barr Virus Viremia.

B cells are involved in chronic graft-versus-host disease (cGVHD) pathogenesis, and Rituximab may have a therapeutic effect on cGVHD in allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients. Herein, we retrospectively evaluated the prophylactic effect of Rituximab on cGVHD in a group of Chinese allo-HSCT patients. A total of 102 patients, who suffered Epstein Barr virus (EBV) viremia within 100 days after allo-HSCT, were included in this study. Fifty patients received Rituximab (375 mg/m2 weekly) for EBV viremia, while fifty-two patients did not receive Rituximab. A competing risk model was adopted to compare cumulative incidence of cGVHD, cumulative incidence of relapse (CIR) and transplantation-related mortality (TRM) between two groups. Cumulative incidence of cGVHD in the Rituximab group was lower than in controls (P = 0.0579). Multivariate analyses confirmed that Rituximab was an independent factor for the reduction of cumulative cGVHD incidence (P = 0.0069). No significant difference was observed in CIR (P = 0.39) or TRM (P = 0.48) between two groups and 2-year OS and DFS were comparable (OS, P = 0.667; DFS, P = 0.571). Administration of Rituximab in the early post-transplantation phase may protect against cGVHD in allo-HSCT patients without increasing CIR or TRM.

Imatinib Mesylate Versus Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Chronic Myelogenous Leukemia.

PURPOSE: To compare the relative merits of imatinib and allogeneic hematopoietic stem cell transplantation (allo-HSCT) for chronic myelogenous leukemia (CML). MATERIALS AND METHODS: This cohort study was designed to compare the outcomes of imatinib (n=292) versus allo-HSCT (n=141) for CML, the clinical data of these patients being retrospectively analyzed so as to compare the event free survival (EFS) and overall survival (OS) between these two groups with patients in the chronic phase (CP) and advanced phases, including accelerate (AP) and blast phases (BP). RESULTS: (1) Patients treated with imatinib (278 in the CP) demonstrated superior EFS, OS, 5-year EFS and 5-year OS rates of 88.5% versus 70.0% (P<0.05), 93.2% versus 80.0% (P<0.05), 84% versus 75.0% (P<0.05) and 92% versus 79.0% (P<0.05), respectively, to those treated with allo-HSCT (120 patients in the CP). (2) Both treatments resulted in similar survival, with EFS and OS rates of 42.9% versus 47.6% (P>0.05), 42.9% versus 57.1% (P>0.05), respectively, for imatinib (14 patients in the AP and BP) and allo-HSCT (21 patients in the AP and BP). CONCLUSIONS: Imatinib confers signi cant survival advantage (EFS and OS) for CML patients with CP compared with allo-HSCT treatment. However, the outcomes are equally good with both treatments in AP and BP patients.