"Double-hit" chronic lymphocytic leukemia: An aggressive subgroup with 17p deletion and 8q24 gain.

Chronic lymphocytic leukemia (CLL) with 17p deletion (17p-) is associated with a lack of response to standard treatment and thus the worst possible clinical outcome. Various chromosomal abnormalities (including unbalanced translocations, deletions, ring chromosomes and isochromosomes) result in the loss of 17p and one copy of the TP53 gene. The objective of the present study was to determine whether the type of chromosomal abnormality leading to 17p- and the additional aberrations influenced the prognosis in a series of 195 patients with 17p-CLL. Loss of 17p resulted primarily from an unbalanced translocation (70%) with several chromosome partners (the most frequent being chromosome 18q), followed by deletion 17p (23%), monosomy 17 (8%), isochromosome 17q [i(17q)] (5%) and a ring chromosome 17 (2%). In a univariate analysis, monosomy 17, a highly complex karyotype (≥5 abnormalities), and 8q24 gain were associated with poor treatment-free survival, and i(17q) (P = .04), unbalanced translocations (P = .03) and 8q24 gain (P = .001) were significantly associated with poor overall survival. In a multivariate analysis, 8q24 gain remained a significant predictor of poor overall survival. We conclude that 17p deletion and 8q24 gain have a synergistic impact on outcome, and so patients with this "double-hit" CLL have a particularly poor prognosis. Systematic, targeting screening for 8q24 gain should therefore be considered in cases of 17p- CLL.

Contribution of MLPA to routine diagnostic testing of recurrent genomic aberrations in chronic lymphocytic leukemia.

To better define the place of multiplex ligation-dependent probe amplification (MLPA) in routine cytogenetic diagnosis in chronic lymphocytic leukemia (CLL), we compared MLPA and fluorescence in situ hybridization (iFISH) data obtained in 77 CLL patients. Although MLPA detected most recurrent copy number genomic aberrations (90.9%), false-negative results were found in cases with small-size abnormal clones and false-positive MLPA findings resulting from point mutations (TP53) or an apparent lack of probe specificity (chromosome 19) were observed. Thus, MLPA may be a useful complementary but not alternative approach for iFISH testing of genomic aberration in CLL.

[Physiopathological, diagnostic and therapeutic impacts of chromosomal translocations in hematological malignancies]. / Translocations récurrentes en onco-hématologie : physiopathologie, intérêt clinique et thérapeutique.

Oncogenesis is correlated with the occurrence of multiple genomic events allowing cancer cells to acquire new properties, including the capacity of survival and proliferation with down regulated control signals. Among those genomic events, the study of recurrent translocations, particularly common in oncohematology, has allowed for a better understanding of leucemogenesis and lymphomagenesis mechanisms. These translocations are classically distinguished depending on their physiopathologic consequences. It may encode for a fusion gene leading to a chimeric protein, which exhibits a new activity or an aberrant one, corresponding in most cases to the constitutive activation of a proto-oncogene. In other cases, these translocations may cause abnormal expression of a proto-oncogene with a regular structure by a transcriptional deregulation. Beyond this highlighting recurrent translocations and understanding better the physiopathologic consequences of these chromosomal modifications has a real impact on patients. These cytogenetic anomalies represent an essential diagnostic tool for some hematologies; and pave the way for a better evaluation of the prognosis and thus, a better adaptation of the therapeutic strategy. They also contributed to improve survival with the development of targeted therapies. Finally, thanks to cytogenetic techniques combined to molecular biology techniques, cytogenetic aberrations can be used as a marker of response, which allowed a monitoring of residual disease.

Autoimmune neutropenia in children: analysis of 116 cases.

Diagnosis of autoimmune neutropenia (AIN) in infants is important, because it allows the exclusion of more severe forms of neutropenia that have an increased risk for leukemia. AIN is characterized by chronic neutropenia, which spontaneously resolves within several months to a few years, and mild infections. Diagnosis is confirmed by the presence of antibodies directed against neutrophil antigens. The human neutrophil antigen (HNA) system is a polymorphic system, which includes five antigen groups with different polymorphisms. In AIN, antibodies are mostly directed against HNA-1 (or against a specific allele of HNA-1) and HNA-4. Here, we present a series of 116 infants with AIN. We observed that anti-neutrophil antibodies were present in 60% cases; directed against HNA-1a in 73% of cases. In addition, we showed there was a bias in the HNA allele distribution in these infants because the frequency of the HNA-1a allele was greater in comparison with controls.

Granulocyte antibody screening: evaluation of a bead-based assay in comparison with classical methods.

BACKGROUND: Granulocyte antibodies have been implicated in allo- and autoimmune neutropenia and in transfusion reactions. STUDY DESIGN AND METHODS: Fifty-one sera from suspected alloimmune neutropenia or transfusion-related acute lung injury (TRALI) and 40 sera from suspected autoimmune neutropenia were tested for granulocyte antibodies using LABScreen MULTI (One Lambda, Inc.), compared with classical tests (flow cytometry [FC] and granulocyte agglutination [GAT] followed by monoclonal antibody-specific immobilization of granulocyte antigens [MAIGA]). RESULTS: In alloimmune situations, 48 sera were concordant (94%), two sera positive for HNA with LABScreen MULTI were negative by FC/GAT and/or MAIGA, and one serum sample negative for HNA with LABScreen MULTI was positive by classical tests. In autoimmune neutropenia, 30 sera were concordant (75%), four sera positive for HNA with LABScreen MULTI were negative by FC/GAT and/or MAIGA, and six sera negative for HNA with LABScreen MULTI were positive by FC/GAT and/or MAIGA. For detection of autoantibodies, the LABScreen MULTI was less concordant. However, with the exception of one case, the discrepancies were observed in sera that did not show a clear specificity. CONCLUSIONS: LABScreen MULTI correlated well with our classical methods for HNA-1 and HNA-2a antibody screening. It can be used for screening blood donors or patients suspected of TRALI, but GAT is still needed for HNA-3a antibody screening.

Essential role for the p110delta isoform in phosphoinositide 3-kinase activation and cell proliferation in acute myeloid leukemia.

The phosphoinositide 3-kinase (PI3K)/Akt signaling pathway has been shown to be frequently activated in blast cells from patients with acute myeloid leukemia (AML) and to contribute to survival and proliferation of these cells. Of the 8 distinct mammalian isoforms of PI3K, it is the class I PI3Ks (p110alpha, p110beta, p110gamma, and p110delta) that are responsible for Akt activation. It is not known which PI3K isoform is critical in AML. Here we show that the p110delta isoform of PI3K is consistently expressed at a high level in blast cells from AML, in contrast to the other class I isoforms, the expression of which was very variable among patients. IC87114, a p110delta-selective inhibitor, suppressed both constitutive and Flt-3-stimulated Akt activation in blasts to the same extent as Ly294002, an inhibitor of all PI3K isoforms. Moreover, IC87114 inhibited AML cell proliferation without affecting the proliferation of normal hematopoietic progenitor cells. These observations identify p110delta as a potential therapeutic target in AML.