Anna Aventin

Prognostic value of minimal residual disease (MRD) in acute myeloid leukemia (AML) with favorable cytogenetics [t(8;21) and inv(16)]

Most patients with acute myeloid leukemia (AML) and t(8;21) or inv(16) have a good prognosis with current anthracycline- and cytarabine-based protocols. Tandem analysis with flow cytometry (FC) and real-time RT-PCR (RQ-PCR) was applied to 55 patients, 28 harboring a t(8;21) and 27 an inv(16), including one case with a novel CBFbeta/MYH11 transcript. A total of 31% (n=17) of CR patients relapsed: seven with t(8;21) and 10 with inv(16). The mean amount of minimal residual disease (MRD) detected by FC in relapsed and nonrelapsed patients was markedly different: 0.3 vs 0.08% (P=0.002) at the end of treatment. The mean number of fusion transcript copies/ABLx104 also differed between relapsed and non-relapsed patients: 2385 vs 122 (P=0.001) after induction, 56 vs 7.6 after intensification (P=0.0001) and 75 vs 3.3 (P=0.0001) at the end of chemotherapy. Relapses were more common in patients with FC MRD level >0.1% at the end of treatment than in patients with ⩽0.1%: cumulative incidence of relapse (CIR) was 67 and 21% (P=0.03), respectively. Likewise, using RQ-PCR, a cutoff level of >10 copies at the end of treatment correlated with a high risk of relapse: CIR was 75% for patients with RQ-PCR >10 compared to 21% for patients with RQ-PCR levels ⩽10 (P=0.04). Combined use of FC and RQ-PCR may improve MRD detection, and provide useful clinical information on relapse kinetics in AML patients.

Additional chromosome abnormalities in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy

Background Acute promyelocytic leukemia is a subtype of acute myeloid leukemia characterized by the t(15;17). The incidence and prognostic significance of additional chromosomal abnormalities in acute promyelocytic leukemia is still a controversial matter. Design and Methods Based on cytogenetic data available for 495 patients with acute promyelocytic leukemia enrolled in two consecutive PETHEMA trials (LPA96 and LPA99), we analyzed the incidence, characteristics, and outcome of patients with acute promyelocytic leukemia with and without additional chromosomal abnormalities who had been treated with all-trans retinoic acid plus anthracycline monochemotherapy for induction and consolidation. Results Additional chromosomal abnormalities were observed in 140 patients (28%). Trisomy 8 was the most frequent abnormality (36%), followed by abn(7q) (5%). Patients with additional chromosomal abnormalities more frequently had coagulopathy (P=0.03), lower platelet counts (P=0.02), and higher relapse-risk scores (P=0.02) than their counterparts without additional abnormalities. No significant association with FLT3/ITD or other clinicopathological characteristics was demonstrated. Patients with and without additional chromosomal abnormalities had similar complete remission rates (90% and 91%, respectively). Univariate analysis showed that additional chromosomal abnormalities were associated with a lower relapse-free survival in the LPA99 trial (P=0.04), but not in the LPA96 trial. However, neither additional chromosomal abnormalities overall nor any specific abnormality was identified as an independent risk factor for relapse in multivariate analysis. Conclusions The lack of independent prognostic value of additional chromosomal abnormalities in acute promyelocytic leukemia does not support the use of alternative therapeutic strategies when such abnormalities are found.

Changes in apoptosis-related pathways in acute myelocytic leukemia

Expression analysis of apoptotic genes was performed for 15 patients with acute myelocytic leukemia (AML) at the time of diagnosis to identify genes and signaling pathways involved in the regulation of cell survival and apoptosis during leukemogenesis. cDNA array analysis revealed 34 genes whose expression was significantly different compared to others. Tumor suppressor genes TP53 and CDKN2A were downregulated and protooncogenes JUN and GRB10 were upregulated. Furthermore, several cellular signaling pathways acting either in cell cycle regulation or in apoptosis were altered. Deregulation was found in pathways that contribute to genomic stability (by downregulation of either TP53 or CSE1L and by upregulation of GADD45A) and regulate cell cycle progression (by downregulation of CDKN2A and upregulation of RBBP4, CDC37, and NEDD5). Alterations at the transcriptional level were identified, namely, upregulation of JUN and E2F5. Abnormalities were observed in the regulation of the caspases through upregulation of CASP8 and by altered expression of BCL2-related pathway. Extrinsic apoptotic signals mediated by IGFs were deregulated and the glutathione detoxification pathway was downregulated. These findings provide insight into the regulation of balance between apoptosis and cell proliferation signals, and suggest that these genes and pathways may have an important role in the pathogenesis of AML.

Beta2-microglobulin is a better predictor of treatment-free survival in patients with chronic lymphocytic leukaemia if adjusted according to glomerular filtration rate.

Even in the era of newer and sophisticated prognostic markers, beta2‐microglobulin (B2M) remains a simple but very powerful predictor of treatment‐free survival (TFS) and overall survival (OS) in patients with chronic lymphocytic leukaemia (CLL). However, B2M levels are heavily influenced by the patient’s glomerular filtration rate (GFR) and this study aimed to evaluate whether GFR‐adjusted B2M (GFR‐B2M) had improved prognostic value compared to unadjusted B2M in a cohort of over 450 consecutive CLL patients from two separate institutions. Multivariate analysis identified a significantly shorter TFS in patients who were ZAP‐70 + (P < 0·001), with increased GFR‐B2M (P < 0·001), and del(11q) or del(17p) as detected by fluorescence in situ hybridization (FISH; P < 0·001). When OS was evaluated by multivariate analysis, age 65 years or older (P < 0·001) and poor risk FISH abnormalities (P < 0·001) had a confirmed adverse prognostic impact, but the predictive value of GFR‐B2M was lost in the validation analysis. In all survival models, B2M did not attain independent significance unless GFR‐B2M was eliminated from the analysis. In conclusion, GFR‐B2M is a better predictor of TFS than unadjusted B2M in CLL patients.

MEIS 1 expression is downregulated through promoter hypermethylation in AML1-ETO acute myeloid leukemias

Retroviral insertional mutagenesis in BXH2 mice commonly induces myeloid leukemias. One of the most frequently involved genes in experimental studies is Meis 1. In contrast to other genes in murine models, Meis 1 has not been affected by recurrent chromosomal translocations or point mutations in human leukemias. We found a constant downregulation of the Meis 1 gene mRNA in AML1-ETO acute myeloid leukemias and in those cases harboring in frame mutations in the bZIP domain of CEBPα. The absence of the Meis 1 mRNA was not caused by inactivating point mutations in the coding sequence. Promoter hypermethylation was present in more than half of the cases (9/14), including samples obtained from the widely employed Kasumi-1 cell line. Double treatment with 5-Aza-2′-deoxycytidine and trichostatin A of the Kasumi-1 cell line partially reverses Meis 1 inhibition. HoxA9 levels were also low. In a cell line model (U937 Tet AML1-ETO), AML1-ETO expression was not associated with Meis 1 suppression at 72 h. Nevertheless, Meis 1 repression is dependent on the AML1-ETO transcript levels in treated leukemic patients. Chimeric products that arise from chromosomal translocations may be associated with locus-specific epigenetic inactivation. It remains to be investigated when this methylation process is acquired and which are the basic mechanisms underlying these molecular events in AML1-ETO and CEBPα-mutated AML.

Bone marrow WT1 levels at diagnosis, post-induction and post-intensification in adult de novo AML.

We retrospectively assessed whether normalized bone marrow WT1 levels could be used for risk stratification in a consecutive series of 584 acute myeloid leukemia (AML) patients. A cutoff value of 5065 copies at diagnosis identified two prognostic groups (overall survival (OS): 44±3 vs 36±3%, P=0.023; leukemia-free survival (LFS): 47±3 vs 36±4%, P=0.038; and cumulative incidence of relapse (CIR): 37±3 vs 47±4%, P=:0.043). Three groups were identified on the basis of WT1 levels post-induction: Group 0 (WT1 between 0 and 17.5 copies, 134 patients, OS: 59±4%, LFS:59±4% and CIR: 26±4%); Group 1 (WT1 between 17.6 and 170.5 copies, 160 patients, OS: 48±5%, LFS:41±4% and CIR: 45±4%); and Group 2 (WT1 >170.5 copies, 71 patients, OS: 23±6%, LFS: 19±7% and CIR: 68±8%) (P<0.001). Post-intensification samples distinguished three groups: patients with WT1 >100 copies (47 patients, 16%); an intermediate group of patients with WT1 between 10 and 100 copies (148 patients, 52%); and a third group with WT1 <10 copies (92 patients, 32%). Outcomes differed significantly in terms of OS (30±7%, 59±4%, 72±5%), LFS (24±7%, 46±4%, 65±5%) and relapse probability (CIR 72±7%, 45±4%, 25±5%), all P<0.001. WT1 levels in bone marrow assayed using the standardized ELN method provide relevant prognostic information in de novo AML.

Variant t(2;18) translocation in a burkitt conversion of follicular lymphoma

We describe here a patient with a low-grade follicular lymphoma evolving to a Burkitt-like lymphoma which at the time of blastic conversion showed multiple chromosome aberrations, including a t(8;22) (q24;q11) typical Burckitt variant translocation associated with a translocation between chromosome 2p11 and chromosome 18q21 which may be an undescribed variant of the t(14;18) follicular lymphoma chromosomal rearrangement

Chronic lymphocytic leukaemia with 17p deletion: a retrospective analysis of prognostic factors and therapy results.

Patients with chronic lymphocytic leukaemia (CLL) whose tumour cells harbour a 17p deletion (17p‐) are universally considered to have a poor prognosis. The deletion can be detected at diagnosis or during the evolution of the disease, particularly in patients who have received chemotherapy. We sought to evaluate the natural history of patients with 17p‐ CLL, identify predictive factors within this prognostic subgroup, and evaluate the results of different therapeutic approaches. Data from 294 patients with 17p‐ CLL followed up at 20 different institutions was retrospectively collected and analysed. Median age was 68 (range 27–98) years at the time of fluorescence in situ hybridization analysis. After 17p‐ documentation, 52% received treatment, achieving an overall response rate of 50%. Median overall survival was 41 months, and was significantly shorter in patients with elevated beta2‐microglobulin concentration (P < 0·001), B symptoms (P = 0·016), higher percentage of cells with deletion (P < 0·001), and acquired deletions (P = 0·012). These findings suggest that patients with 17p‐ CLL have a variable prognosis that can be refined using simple clinical and laboratory features, including 17p‐ clone size, beta2‐microglobulin concentration, presence of B symptoms and type of deletion (de novo versus acquired).

CIZ gene rearrangements in acute leukemia: report of a diagnostic FISH assay and clinical features of nine patients

CIZ gene rearrangements in acute leukemia: report of a diagnostic FISH assay and clinical features of nine patients

Genomic organization of human JAK2 and mutation analysis of its JH2-domain in leukemia

The Janus kinase family of proteins, with four mammalian members (JAK1, JAK2, JAK3 and TYK2), plays an essential role in the signal transduction pathway from non-catalytic cytokine receptors to the nucleus. We recently reported the involvement of ETV6-JAK2 fusion genes in the development of leukemia of both lymphoid and myeloid origin. Dominant missense mutations of hopscotch, a Drosophila JAK homologue, causing leukemia-like defects were described. One of these mutations affected a conserved residue of the kinase- like JH2 domain and the introduction of this mutation in murine Jak2 resulted in the constitutional activation of its kinase activity. In order to further analyze its role in leukemogenesis, we cloned human JAK2 and determined its genomic organization. Twenty-four exons spanning a region of approximately 150 kb were identified. A mutation analysis of the exons 13 to 19, encoding the kinase-like JH2 domain failed to detect activating mutations in leukemia samples, suggesting that this is a rare event in human leukemia.