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Validation of ZAP-70 methylation and its relative significance in predicting outcome in chronic lymphocytic leukemia.

ABSTRACT: ZAP-70 methylation 223 nucleotides downstream of transcription start (CpG+223) predicts outcome in chronic lymphocytic leukemia (CLL), but its impact relative to CD38 and ZAP-70 expression or immunoglobulin heavy chain variable region (IGHV) status is uncertain. Additionally, standardizing ZAP-70 expression analysis has been unsuccessful. CpG+223 methylation was quantitatively determined in 295 untreated CLL cases using MassARRAY. Impact on clinical outcome vs CD38 and ZAP-70 expression and IGHV status was evaluated. Cases with low methylation (<20%) had significantly shortened time to first treatment (TT) and overall survival (OS) (P < .0001). For TT, low methylation defined a large subset of ZAP-70 protein-negative cases with significantly shortened TT (median, 8.0 vs 3.9 years for high vs low methylation; hazard ratio [HR] = 0.43; 95% confidence interval [CI], 0.25-0.74). Conversely, 16 ZAP-70 protein-positive cases with high methylation had poor outcome (median, 1.1 vs 2.3 years for high vs low methylation; HR = 1.62; 95% CI, 0.87-3.03). For OS, ZAP-70 methylation was the strongest risk factor; CD38 and ZAP-70 expression or IGHV status did not significantly improve OS prediction. A pyrosequencing assay was established that reproduced the MassARRAY data (? coefficient > 0.90). Thus, ZAP-70 CpG+223 methylation represents a superior biomarker for TT and OS that can be feasibly measured, supporting its use in risk-stratifying CLL.

SUBMITTER: Claus R

PROVIDER: S-EPMC4125353 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Validation of ZAP-70 methylation and its relative significance in predicting outcome in chronic lymphocytic leukemia.

Claus Rainer R Lucas David M DM Ruppert Amy S AS Williams Katie E KE Weng Daniel D Patterson Kara K Zucknick Manuela M Oakes Christopher C CC Rassenti Laura Z LZ Greaves Andrew W AW Geyer Susan S Wierda William G WG Brown Jennifer R JR Gribben John G JG Barrientos Jacqueline C JC Rai Kanti R KR Kay Neil E NE Kipps Thomas J TJ Shields Peter P Zhao Weiqiang W Grever Michael R MR Plass Christoph C Byrd John C JC

Blood 20140527 1

ZAP-70 methylation 223 nucleotides downstream of transcription start (CpG+223) predicts outcome in chronic lymphocytic leukemia (CLL), but its impact relative to CD38 and ZAP-70 expression or immunoglobulin heavy chain variable region (IGHV) status is uncertain. Additionally, standardizing ZAP-70 expression analysis has been unsuccessful. CpG+223 methylation was quantitatively determined in 295 untreated CLL cases using MassARRAY. Impact on clinical outcome vs CD38 and ZAP-70 expression and IGHV ...[more]

PMID: 24868078

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Project description:Several studies demonstrated IgVH mutation status and ZAP-70 expression as the most relevant prognostic markers in CLL, suggesting the separation of two patient subgroups: with good (MTZAP-70-) and poor prognosis (UMZAP-70+). We determined gene expression of B cells in 112 CLL patients divided into three classes: the first with IgVHMT and ZAP-70-, the second with IgVHUM and ZAP-70+, and the third included both IgVHUM ZAP-70- and IgVHMT ZAP-70+. We found LPL, AGPAT2, MBOAT1, CHPT1, AGPAT4, PLD1 genes encoding enzymes involved in lipid (glycerolipid/glycerophospholipid) metabolism overexpressed in UMZAP-70+. In addition, this study demonstrates the role of ARSD, a gene belonging to the sphingolipid metabolism, as a new gene significantly overexpressed in UMZAP-70+ in respect to MTZAP-70-. ARSD protein was found at significantly higher concentrations in UMZAP-70+ compared to MTZAP-70- CLL B cells and B cells from healthy individuals by Western blotting. Statistical analysis identified a strong correlation between ARSD and IgVH mutation status; ARSD protein level was associated with the requirement of therapy for CLL patients and for this purpose it is as good as IgVH mutational status. Our study highlights ARSD as a promising new prognostic factor in CLL and sphingolipid metabolism as a putative new biological mechanism in CLL. In this study we performed gene expression profiling of B cells on 112 CLL patients divided into three classes based on IgVH mutational status and ZAP-70 protein expression: class one with mutated IgVH and ZAP-70-, class two with unmutated IgVH and ZAP-70+, and class three included CLL patients with unmutated IgVH and ZAP-70-, or mutated IgVH and ZAP-70+, respectively. The decision to divide CLL patients in three categories was due to the clinical feature and the molecular heterogeneity of CLL, in order to elaborate different molecular signature capable of reveal biological mechanisms, and to identify new potential molecular predictors for prognostic assessment or genetic risk. RNA was extracted and quantified for high-density oligonucleotide microarrays Human Genome U133 Plus 2.0 GeneChip (Affymetrix, Santa Clara, CA). A first cohort of 62 subjects was analyzed using GeneChip Expression 3' Amplification One-Cycle Target Labeling Kit, while a second cohort of 50 subjects using GeneChip 3'IVT Express Kit, according to manufacturerM-bM-^@M-^Ys protocol (Affymetrix), respectively.

Dataset Information

Validation of ZAP-70 methylation and its relative significance in predicting outcome in chronic lymphocytic leukemia.

Publications

Validation of ZAP-70 methylation and its relative significance in predicting outcome in chronic lymphocytic leukemia.

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