Telomere length is an independent predictor of survival, treatment requirement and Richter's syndrome transformation in chronic lymphocytic leukemia

Telomere length (TL) has been associated with outcome in chronic lymphocytic leukemia (CLL). This extensive analysis assess TL on 401 CLL patients subdivided in one cohorts of patients used as learning (191 patients) and one as blinded validation series (210 patients). A TL cutoff of 5000 bp was chosen by receiver operating characteristic (ROC) analysis and Youden\u2019s index in the learning series. In this series,TLp5000 bp was independently associated to a worse outcome for both overall survival (OS; 105.5 vs 281 months, Po0.001) and treatment-free survival (TFS; 24.6 vs 73 months, Po0.001).In the blinded validation series, TLp5000 bp was confirmed as an independent outcome predictor for OS (79.8 vs not reached, Po0.001) and TFS (15.2 vs 130.8 months, Po0.001). Moreover, TLp5000 bp independently predicted the risk of Richter\u2019s syndrome (5-year risk: 18.9 vs 6.4%, P\ubc0.016). Within CLL subsets defined by biological predictors, TL consistently identified patient subgroups harboring unfavorable prognosis. These results demonstrate that TL is a powerful independent predictor of multiple outcomes in CLL, and contributes to refine the prognostic assessment of this disease when utilized in combination with other prognostic markers. We thus believe that this prognostic biomarker has the potential for a more widespread use in CLL.Telomere length (TL) has been associated with outcome in chronic lymphocytic leukemia (CLL). The aim of this extensive analysis carried out on 401 CLL patients was to assess TL conclusively as a prognostic biomarker. Our study included two cohorts used as learning (191 patients) and blinded validation series (210 patients). A TL cutoff of 5000 bp was chosen by receiver operating characteristic (ROC) analysis and Youden's index in the learning series. In this series, TL< or =5000 bp was independently associated to a worse outcome for both overall survival (OS; 105.5 vs 281 months, P<0.001) and treatment-free survival (TFS; 24.6 vs 73 months, P<0.001). In the blinded validation series, TL< or =5000 bp was confirmed as an independent outcome predictor for OS (79.8 vs not reached, P<0.001) and TFS (15.2 vs 130.8 months, P<0.001). Moreover, TL< or =5000 bp independently predicted the risk of Richter's syndrome (5-year risk: 18.9 vs 6.4%, P=0.016). Within CLL subsets defined by biological predictors, TL consistently identified patient subgroups harboring unfavorable prognosis. These results demonstrate that TL is a powerful independent predictor of multiple outcomes in CLL, and contributes to refine the prognostic assessment of this disease when utilized in combination with other prognostic markers. We thus believe that this prognostic biomarker has the potential for a more widespread use in CLL

Usefulness of JAK2V617F mutation in distinguishing idiopathic erythrocytosis from polycythemia vera

Idiopathic erythrocytosis (IE) is a primary erythrocytosis not fulfilling the criteria for polycythemia vera (PV) diagnosis. In order to verify the relationship between IE and PV, we screened JAK2V617F mutation in a consecutive series of 11 IE and, for comparison, in 15 PV. JAK2V617F mutation was screened by both cDNA sequencing and mutation specific PCR in both peripheral blood and bone marrow samples. All 11 IE tested negative for JAK2V617F mutation, which, conversely, occurred in 11/15 (73.3%) PV. Our results demonstrate that JAK2V617F is absent in IE and may represent a useful molecular marker for distinguishing IE from PV

FREQUENT SILENCING OF FRAGILE HISTIDINE TRIAD GENE (FHIT) IN BURKITT\u2019s LYMPHOMA IS ASSOCIATED WITH ABERRANT HYPERMETHYLATION

The fragile histidine triad (FHIT) gene, a potential tumor-suppressor gene, is frequently inactivated in multiple human cancers. However, the FHIT gene remains largely unexplored in Burkitt's lymphoma (BL). Hence, we assessed whether loss of FHIT expression occurs in BL, and, if so, what is the mechanism of such loss. Lack of protein expression was observed in 50% of BL cell lines. Methylation-specific polymerase chain reaction (MSP) showed that 45% of BL cell lines carried aberrantly methylated FHIT alleles. Sequencing of bisulfite-treated DNA confirmed these data and indicated a very high density of methylation in all methylated alleles. Real-time, quantitative reverse-transcription PCR analysis indicated that attenuation of full-length FHIT transcription was correlated with methylation. Sequencing of transcripts illustrated that aberrant transcription resulting in loss of FHIT exons occurred more commonly in BL containing unmethylated FHIT genes. However, such transcripts often coexisted with full-length FHIT transcripts. Not surprisingly, therefore, loss of FHIT protein in BL correlated with CpG island methylation, rather than with aberrant transcription. FHIT methylation also was detected in 31% (16 of 51) of the primary BLs examined, including 2 samples whose derived cell lines also manifested FHIT hypermethylation. Aberrant methylation can thus occur in vivo. In summary, this report provides evidence that epigenetic modification frequently results in loss of FHIT expression in BL

EPIGENETIC INACTIVATION OF SUPPRESSORS OF CYTOKINE SIGNALLING IN Ph-NEGATIVE CHRONIC MYELOPROLIFERATIVE DISORDERS

Ph-negative chronic myeloproliferative disorders (CMPD) are characterized by constitutive Janus kinase-signal transducer and activator of transcription (JAK-STAT) activation. SOCS3, SOCS1 and PTPN6 (SHP1) are negative regulators of the JAK-STAT pathway. We investigated epigenetic and genetic inactivation of SOCS3, SOCS1 and PTPN6 in 112 CMPD and 20 acute myeloid leukaemia (AML) post-CMPD. SOCS3 methylation occurred at high frequency in both CMPD (46/112; 41.1%) and AML post-CMPD (10/17; 58.8%) and was associated with transcriptional silencing. In contrast, methylation of SOCS1 and PTPN6 was observed in only a fraction of CMPD (15/112, 13.4% for SOCS1; and 8/112, 7.1% for PTPN6) and AML post-CMPD (3/20, 15% for SOCS1; and 1/20, 5% for PTPN6). No somatic mutations of SOCS1 were found in CMPD. SOCS3, SOCS1 and PTPN6 methylation occurred in both JAK2V617F-positive (35.1% for SOCS3; 14.9% for SOCS1; 8.1% for PTPN6) and JAK2V617F-negative (57.1% for SOCS3; 14.3% for SOCS1; and 9.5% for PTPN6) CMPD. These data indicate that methylation of SOCS3 and, to a lesser extent, SOCS1 and PTPN6 is a frequent event in both JAK2V617F-positive and -negative CMPD and may act as an alternative or complementary mechanism to JAK2 mutations, enhancing cytokine signal transduction. The frequent inactivation of SOCS3 is a novel finding in CMPD with potential implications for the molecular pathology of these disorders