title: 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 (κ 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.
authors.affiliation: Division of Hematology, Oncology, and Stem Cell Transplantation, University of Freiburg Medical Center, Freiburg, Germany; Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center, Heidelberg, Germany;
authors.forename: Rainer
authors.initials: R
authors.lastname: Claus
authors.affiliation: Division of Hematology and.
authors.forename: David M
authors.initials: DM
authors.lastname: Lucas
authors.affiliation: Division of Hematology and.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Ruppert
authors.affiliation: Division of Hematology and.
authors.forename: Katie E
authors.initials: KE
authors.lastname: Williams
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine and the Comprehensive Cancer Center, and.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weng
authors.affiliation: Division of Hematopathology, Department of Pathology and the Comprehensive Cancer Center, The Ohio State University, Columbus, OH;
authors.forename: Kara
authors.initials: K
authors.lastname: Patterson
authors.affiliation: Division of Biostatistics, German Cancer Research Center, Heidelberg, Germany;
authors.forename: Manuela
authors.initials: M
authors.lastname: Zucknick
authors.affiliation: Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center, Heidelberg, Germany;
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Oakes
authors.affiliation: Division of Hematology-Oncology and Central Office of CLL Research Consortium, Moores Cancer Center, University of California San Diego, La Jolla, CA;
authors.forename: Laura Z
authors.initials: LZ
authors.lastname: Rassenti
authors.affiliation: Division of Hematology-Oncology and Central Office of CLL Research Consortium, Moores Cancer Center, University of California San Diego, La Jolla, CA;
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Greaves
authors.affiliation: Division of Hematology and.
authors.forename: Susan
authors.initials: S
authors.lastname: Geyer
authors.affiliation: Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX;
authors.forename: William G
authors.initials: WG
authors.lastname: Wierda
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA;
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Brown
authors.affiliation: Institute of Cancer, Centre for Medical Oncology, Barts and The London School of Medicine, University of London, London, United Kingdom;
authors.forename: John G
authors.initials: JG
authors.lastname: Gribben
authors.affiliation: Division of Hematology-Oncology, North Shore-Long Island Jewish Health System, New Hyde Park, NY; and.
authors.forename: Jacqueline C
authors.initials: JC
authors.lastname: Barrientos
authors.affiliation: Division of Hematology-Oncology, North Shore-Long Island Jewish Health System, New Hyde Park, NY; and.
authors.forename: Kanti R
authors.initials: KR
authors.lastname: Rai
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN.
authors.forename: Neil E
authors.initials: NE
authors.lastname: Kay
authors.affiliation: Division of Hematology-Oncology and Central Office of CLL Research Consortium, Moores Cancer Center, University of California San Diego, La Jolla, CA;
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Kipps
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine and the Comprehensive Cancer Center, and.
authors.forename: Peter
authors.initials: P
authors.lastname: Shields
authors.affiliation: Division of Hematopathology, Department of Pathology and the Comprehensive Cancer Center, The Ohio State University, Columbus, OH;
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Division of Hematology and.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Grever
authors.affiliation: Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center, Heidelberg, Germany;
authors.forename: Christoph
authors.initials: C
authors.lastname: Plass
authors.affiliation: Division of Hematology and.
authors.forename: John C
authors.initials: JC
authors.lastname: Byrd
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D019175:DNA Methylation / Q000235:genetics*; D005260:Female; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics; D053208:Kaplan-Meier Estimate; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000378:metabolism / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000235:genetics* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D007135:Immunoglobulin Variable Region; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human