Targeting the tyrosine kinase activity of BCR-ABL represents a very promising therapeutic strategy in chronic myeloid leukemia (CML). Despite strong efficacy of the tyrosine kinase inhibitor STI571, resistance has been observed in a significant proportion of patients in advanced CML stage or in Ph-positive acute lymphoid leukemia (ALL). We investigated in this study the mechanism of resistance to

Key Points• In adult ALL, oncogenetic markers and minimal residual disease levels are independent outcome predictors.• Both factors should be used for individual treatment stratification.With intensified pediatric-like therapy and genetic disease dissection, the field of adult acute lymphoblastic leukemia (ALL) has evolved recently. In this new context, we aimed to reassess the value of conventional risk factors with regard to new genetic alterations and early response to therapy, as assessed by immunoglobulin/T-cell receptor minimal residual disease (MRD) levels. The study was performed in 423 younger adults with Philadelphia chromosome-negative ALL in first remission (265 B-cell precursor [BCP] and 158 T-cell ALL), with cumulative incidence of relapse (CIR) as the primary end point. In addition to conventional risk factors, the most frequent currently available genetic alterations were included in the analysis. A higher specific hazard of relapse was independently associated with postinduction MRD level ‡10 24 and unfavorable genetic characteristics (ie, MLL gene rearrangement or focal IKZF1 gene deletion in BCP-ALL and no NOTCH1/FBXW7 mutation and/or N/K-RAS mutation and/or PTEN gene alteration in T-cell ALL). These 2 factors allowed definition of a new risk classification that is strongly associated with higher CIR and shorter relapse-free and overall survival. These results indicate that genetic abnormalities are important predictors of outcome in adult ALL not fully recapitulated by early response to therapy. Patients included in this study were treated in the multicenter GRAALL-2003 and GRAALL-2005 trials. Both trials were registered at

Key Points• The MYD88 locus is altered in 91% of patients with WM. • MYD88 might be new target for therapeutic in WM.Mutation of the MYD88 gene has recently been identified in activated B-cell-like diffuse cell lymphoma and enhanced Janus kinase/signal transducer and activator of transcription (JAK-STAT) and nuclear factor kB (NF-kB) signaling pathways. A whole exome-sequencing study of Waldenstrom macroglobulinemia (WM) suggested a high frequency of MYD88 L265P mutation in WM. The genetic background is not fully deciphered in WM, although the role of NF-kB and JAK-STAT has been demonstrated. We analyzed MYD88 mutation in exon 5 and characterized the clinical significance of this genetic alteration in 67 WM patients. Clinical features; immunophenotypic markers; and conventional cytogenetic, fluorescence in situ hybridization, and single nucleotide polymorphism array data were analyzed. MYD88 L265P mutation was acquired in 79% of patients. Overall, we have identified alteration of the MYD88 locus in 91% of WM patients, including 12% with gain on chromosome 3 at the 3p22 locus that included the MYD88 gene. Patients with absence of MYD88 mutation were WM characterized with a female predominance, a splenomegaly, gain of chromosome 3, and CD27 expression. Importantly, inhibition of MYD88 signaling induced cytotoxicity and inhibited cell growth of cell lines issued from patients with WM. In conclusion, these results confirm a high frequency of MYD88 L265P mutation in WM. The discovery of MYD88 L265P mutation may contribute to a better understanding of the physiopathogeny of WM. (Blood. 2013;121(22):4504-4511)

In a series of 153 children with T-cell malignancies enrolled in 2 consecutive European Organization for Research and Treatment of Cancer (EORTC) trials, we assessed the HOX11L2 expression and/or the presence of a t(5;14)(q35;q32). Additionally, in 138 of these patients, HOX11 expression and SIL-TAL rearrangement were also assessed. These alterations were mutually exclusive, and their frequency was 23% (n ‫؍‬ 35), 7% (n ‫؍‬ 10), and 12% (n ‫؍‬ 17), respectively. HOX11L2/ t(5;14) positivity was more frequent in acute lymphoblastic leukemia (ALL) with cortical T immunophenotype and in children aged between 6 and 9 years. In contrast with previously reported data, patients positive and negative for HOX11L2/t(5;14) were comparable with regard to clinical outcome as well as to the response to a 7-day prephase treatment or to residual disease at completion of induction therapy.

Risk-adjusted treatment stratification in T-cell acute lymphoblastic leukemias (T-ALLs) is currently based only on early response to chemotherapy. We investigated the prognostic implication of hyperactivation of NOTCH pathway resulting from mutations of NOTCH1 or FBXW7 in children with T-ALL enrolled in EORTC-CLG trials. Overall, 80 out of 134 (60%) patients were NOTCH þ (NOTCH1 and/or FBXW7 mutated). Although clinical presentations were not significantly associated with NOTCH status, NOTCH þ patients showed a better early response to chemotherapy as compared with NOTCHÀ patients, according to the rate of poor pre-phase 'responders' (25% versus 44%; P ¼ 0.02) and the incidence of high minimal residual disease (MRD) levels (11% (7/62) versus 32% (10/31); P ¼ 0.01) at completion of induction. However, the outcome of NOTCH þ patients was similar to that of NOTCHÀ patients, with a 5-year event-free survival (EFS) of 73% and 70% (P ¼ 0.82), and 5-year overall survival of 82% and 79% (P ¼ 0.62), respectively. In patients with high MRD levels, the 5-year EFS rate was 0% (NOTCH þ ) versus 42% (NOTCHÀ), whereas in those with low MRD levels, the outcome was similar: 76% (NOTCH þ ) versus 78% (NOTCHÀ). The incidence of isolated central nervous system (CNS) relapses was relatively high in NOTCH1 þ patients (8.3%), which could be related to a higher propensity of NOTCH þ leukemic blasts to target the CNS.