Wide diversity of PAX5 alterations in B-ALL: a Groupe Francophone de Cytogenetique Hematologique study.

PAX5 is the main target of somatic mutations in acute B lymphoblastic leukemia (B-ALL). We analyzed 153 adult and child B-ALL harboring karyotypic abnormalities at chromosome 9p, to determine the frequency and the nature of PAX5 alterations. We found PAX5 internal rearrangements in 21% of the cases. To isolate fusion partners, we used classic and innovative techniques (rolling circle amplification-rapid amplification of cDNA ends) and single nucleotide polymorphism-comparative genomic hybridization arrays. Recurrent and novel fusion partners were identified, including NCoR1, DACH2, GOLGA6, and TAOK1 genes showing the high variability of the partners. We noted that half the fusion genes can give rise to truncated PAX5 proteins. Furthermore, malignant cells carrying PAX5 fusion genes displayed a simple karyotype. These data strongly suggest that PAX5 fusion genes are early players in leukemogenesis. In addition, PAX5 deletion was observed in 60% of B-ALL with 9p alterations. Contrary to cases with PAX5 fusions, deletions were associated with complex karyotypes and common recurrent translocations. This supports the hypothesis of the secondary nature of the deletion. Our data shed more light on the high variability of PAX5 alterations in B-ALL. Therefore, it is probable that gene fusions occur early, whereas deletions should be regarded as a late/secondary event.

Central nervous system involvement in adult acute lymphoblastic leukemia at diagnosis and/or at first relapse: results from the GET-LALA group.

Outcome of adult acute lymphoblastic leukemia (ALL) with central nervous system (CNS) involvement is not clearly defined. We studied 104 patients presenting with CNS involvement at diagnosis among 1493 patients (7%) included into the LALA trials, and 109 patients presenting CNS disease at the time of first relapse among the 709 relapsing patients (15%). Eighty-seven patients (84%) with CNS leukemia at diagnosis achieved complete remission (CR). Fifty-three patients underwent stem cell transplantation (SCT): 25 allogeneic SCT, 28 autologous SCT, while 34 continued with chemotherapy alone. Seven-year overall survival (OS) and disease-free survival (DFS) were 34% and 35%, respectively. There were no significant differences in terms of CR, OS and DFS among patients with CNS involvement at diagnosis and those without CNS disease. There were also no differences among the two groups regarding T lineage ALL, B lineage ALL, and among those who underwent SCT. After a first relapse, 38 patients with CNS recurrence (35%) achieved a second CR. The median OS was 6.3 months. Outcome was similar to that of relapsing patients without CNS disease. CNS leukemia in adult ALL is uncommon at diagnosis as well as at the time of first relapse. With intensification therapy, patients with CNS leukemia at diagnosis have a similar outcome than those who did not present with CNS involvement. CNS leukemia at first relapse remains of similar poor prognosis than all other adult ALL in first relapse.

Abnormalities of the long arm of chromosome 21 in 107 patients with hematopoietic disorders: a collaborative retrospective study of the Groupe Français de Cytogénétique Hématologique.

Chromosome 21 is frequently rearranged in hematopoietic malignancies. In order to detect new chromosomal aberrations, the Groupe Français de Cytogénétique Hématologique collected a series of 107 patients with various hematologic disorders and acquired structural abnormalities of the long arm of chromosome 21. The abnormalities were subclassified into 10 groups, according to the location of the 21q breakpoint and the type of abnormality. Band 21q22 was implicated in 72 patients (excluding duplications, triplications, and amplifications). The involvement of the RUNX1 gene was confirmed in 10 novel translocations, but the gene partners were not identified. Eleven novel translocations rearranging band 21q22 with bands 1q25, 2p21, 2q37, 3p21, 3p23, 4q31, 6p24 approximately p25, 6p12, 7p15, 16p11, and 18q21 were detected. Rearrangements of band 21q11 and 21q21 were detected in six novel translocations with 5p15, 6p21, 15q21, 16p13, and 20q11 and with 1p33, 3q27, 5p14, 11q11, and 14q11, respectively. Duplications, triplications, amplifications, and isodicentric chromosomes were detected in eight, three, eight, and three patients, respectively. The present study shows both the wide distribution of the breakpoints on the long arm of chromosome 21 in hematopoietic malignancy and the diversity of the chromosomal rearrangements and the hematologic disorders involved. The findings invite further investigation of the 21q abnormalities to detect their associated molecular rearrangements.

Outcome of treatment in adults with acute lymphoblastic leukemia: analysis of the LALA-94 trial.

PURPOSE: We analyzed the benefits of a risk-adapted postremission strategy in adult lymphoblastic leukemia (ALL), and re-evaluated stem-cell transplantation (SCT) for high-risk ALL. PATIENTS AND METHODS: A total of 922 adult patients entered onto the trial according to risk groups: standard-risk ALL (group 1), high-risk ALL (group 2), Philadelphia chromosome-positive ALL (group 3), and CNS-positive ALL (group 4). All received a standard four-drug/4-week induction course. Patients from group 1 who achieved a complete remission (CR) after one course of induction therapy were randomly assigned between intensive and less intensive postremission chemotherapy, whereas those who achieved CR after salvage therapy were then included in group 2. Patients in groups 2, 3, and 4 with an HLA-identical sibling were assigned to allogeneic SCT. In groups 3 and 4, autologous SCT was offered to all other patients, whereas in group 2 they were randomly assigned between chemotherapy and autologous SCT. RESULTS: Overall, 771 patients achieved CR (84%). Median disease-free survival (DFS) was 17.5 months, with 3-year DFS at 37%. In group 1, the 3-year DFS rate was 41%, with no difference between arms of postremission randomization. In groups 2 and 4, the 3-year DFS rates were 38% and 44%, respectively. In group 2, autologous SCT and chemotherapy resulted in comparable median DFS. Patients with an HLA-matched sibling (groups 2 and 4) had improved DFS. Three-year DFS was 24% in group 3. CONCLUSION: Allogeneic SCT improved DFS in high-risk ALL in the first CR. Autologous SCT did not confer a significant benefit over chemotherapy for high-risk ALL.

A report from the LALA-94 and LALA-SA groups on hypodiploidy with 30 to 39 chromosomes and near-triploidy: 2 possible expressions of a sole entity conferring poor prognosis in adult acute lymphoblastic leukemia (ALL).

To reveal the relationship between hypodiploidy with 30 to 39 chromosomes and near-triploidy in acute lymphoblastic leukemia (ALL), we studied 24 patients presenting with one of these aneuploidies among 623 adults with ALL registered in the Leucemie Aigue Lymphoblastique de l'Adulte (LALA) protocols. The 2 ploidy groups presented a striking similarity of their cytogenetic profiles: chromosomes 2, 3, 4, 7, 13, 15, 16, and 17, significantly monosomic in hypodiploidy 30 to 39, were also frequently disomic in near-triploidy, whereas those retained in pairs in hypodiploidy 30 to 39 were frequently tetrasomic in near-triploidy. DNA content data revealed the simultaneous presence of 2 aneuploid peaks in most tested cases (DNA indexes: 0.72-0.87/1.39-1.89) and a multiple correspondence analysis applied on cytogenetic profiles ascertained their strong relationship. We thus assumed that near-triploidy derives from the duplication of hypodiploidy with 30 to 39 chromosomes and that both aneuploid groups are 2 expressions of the same disease. These 24 patients presented with B-cell phenotype, low leukocytoses (median white blood cell count, 4.2 x 10(9)/L), and poor prognosis (complete remission, 57%; median disease-free-survival, 8 months; median survival, 10.4 months) comparable to that of Ph(+) patients treated according to the same protocol. We suggest that hypodiploidy with 30 to 39 chromosomes or near-triploidy should be regarded as a new high-risk factor in the risk stratification of adult ALL protocols.

CALM-AF10 is a common fusion transcript in T-ALL and is specific to the TCRgammadelta lineage.

The t(10;11)(p13-14;q14-21) associated with CALM-AF10 is considered to be rare and associated with a variety of acute lymphoid and myeloid leukemias. Twelve (9%) of 131 unselected T-cell acute lymphoid leukemias (T-ALLs) expressed CALM-AF10 by reverse transcription-polymerase chain reaction or fluorescence in situ hybridization (or both), including 8% of children and 10% of adults, of whom only half demonstrated a t(10;11) by classical cytogenetics. CALM-AF10 was not found in T-cell-receptor alphabeta (TCRalphabeta) lineage T-ALLs, as defined by expression of TCRalphabeta, cytoplasmic TCRbeta, or TCRbetaVDJ rearrangement in immature cytoplasmic TCRbeta- cases, compared with 19% of TCRgammadelta T-ALLs and 33% of immature delta/gamma T-ALLs. The latter differed from their CALM-AF10- immature counterparts by a CD5+/CD2-phenotype, as found in TCRgammadelta but not TCRalphabeta T-ALLs and in their TCRgamma and TCRdelta configurations, altogether suggesting that CALM-AF10+ immature delta/gammaT-ALLs are TCRgammadelta precursors and that, within T-ALL, CALM-AF10 is specific for this lineage. Nine of 12 immature CALM-AF10 T-ALLs demonstrated 3' fusion transcripts, whereas 6 of 7 TCRgammadelta T-ALLs demonstrated 5' fusion transcripts. The latter retain the AF10 extended LAP/PHD domain necessary for homo-oligomerization. All 8 patients with CALM-AF10+TCRgammadelta T-ALLs are alive, compared with only 3 of 12 with immature CALM-AF10+ T-ALLs. Six CALM-AF10+ non-T acute leukemias all expressed CD7 and demonstrated T-restricted TCRdelta rearrangements, suggesting that they may also be related to the TCRgammadelta lineage. CALM-AF10 is therefore the most common fusion protein in T-ALL. It requires molecular and immunophenotypic characterization for appropriate prognostic evaluation and should be included in diagnostic screening panels of T-ALL and immature acute leukemias. Analysis of immature CALM-AF10+ leukemias will also facilitate analysis of the early stages of development of the TCRgammadelta lineage.

Outcome of treatment in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia--results of the prospective multicenter LALA-94 trial.

From 1994 to 2000, 154 adults with Philadelphia chromosome-positive (Ph(+)) and/or BCR-ABL(+) acute lymphoblastic leukemia (ALL) were treated according to a prospective trial (median follow-up, 4.5 years) with the aim to study the prognostic value of early response to therapy and the role of stem cell transplantation (SCT) in first complete remission (CR). All patients received a standard induction course followed by a course of mitoxantrone and intermediate-dose cytarabine (HAM). After each course, minimal residual disease was tested by specific reverse transcriptase-polymerase chain reaction (RT-PCR) (median sensitivity, 10(-5)). Allogeneic SCT (if a donor) or autologous SCT (if not) was planned at 3 months in all patients in CR after HAM. CR rates after induction, after HAM, and at 3 months were 53%, 67%, and 62%, respectively. High leukocyte count and m-bcr subtype were the 2 identified bad-prognosis factors for CR at 3 months, both superseded by a poor early response assessed at day 8 of the induction course. HAM-associated salvage rate was higher in patients with M-bcr than in those with m-bcr ALL (55% vs 30%; P =.05). In the 103 patients eligible for SCT, the existence of a donor and the negative BCR-ABL status after HAM were independently predictive of remission duration (P <.001 and.01, respectively) and survival (P =.02 and.01, respectively). Relapse was the most common cause of treatment failure in all patient groups. Allogeneic SCT in first CR is the current best treatment option in adults with the disease. New strategies must be tested during early phases of therapy to increase the rate of BCR-ABL(-) remissions.

Structural rearrangements of chromosome 3 in 57 patients with acute myeloid leukemia: clinical, hematological and cytogenetic features.

INTRODUCTION: Structural rearrangements of chromosome 3q have been described in approximately 2% of patients with acute myeloid leukemia. Breakpoints are mainly located in the 3q21 and 3q26 regions but may occur elsewhere on chromosome 3. To determine the relationship between these breakpoints and the hematological parameters, including outcome of these patients, we analysed data from newly diagnosed adult AML patients with 3q rearrangements referred to our institution over a 15-year period. MATERIALS AND METHODS: This retrospective study was conducted using data from 57 AML patients (median age: 64 years, range 19-82) with 3q rearrangements. Cytogenetic analysis was performed using standard techniques (RHG banding, FISH). Data concerning AML patients with 3q abnormalities were compared for outcome with those from patients with normal karyotype and from patients with 5q deletion, treated according to the same intensive protocols for the same time period. RESULTS: Patients with myeloid malignancy displaying 3q rearrangement were assigned to five subgroups, including those with: 3q21/q26 rearrangement; 3q21 alone, including t(1;3)(p36;q21); 3q26 alone, resulting in translocations involving multiple chromosome partners; t(3;5); 3q deletions. Among these patients, 37 were treated in AML chemotherapy trials. Complete remission was achieved in 43% (26/57) of cases. Five patients died early. Sixteen patients were resistant to induction chemotherapy. Median DFS and median OS were 4.5 and 8.8 months respectively. Relapse was observed in 34% of patients achieving CR. Comparison of the outcome of CR patients with that of patients presenting with normal karyotype (intermediate-risk) or complete/partial 5q deletion (high-risk) confirmed the very poor prognosis of patients carrying 3q chromosomal rearrangements. CONCLUSION: These data confirm that 3q rearrangements at q21 or q26 are recurring chromosomal abnormalities in AML. Appearing frequently in combination with monosomy 7 and an abnormal megakaryopoiesis, patients with these abnormalities have a particularly poor prognosis.