The currently used prognostic models for patients with non-metastatic clear cell renal cell carcinoma (ccRCC) are based on clinicopathological features and might be improved by adding molecular markers. Epigenetic alterations occur frequently in ccRCC and are promising biomarkers. The aim of this study is to identify prognostic promoter methylation markers for ccRCC.
We integrated data generated by massive parallel sequencing of methyl-binding domain enriched DNA and microarray based RNA expression profiling of 5-aza-2'-deoxycytidine treated ccRCC cell lines to comprehensively characterize the ccRCC methylome. A selection of the identified methylation markers was evaluated in two independent series of primary ccRCC (n=150 and n=185) by methylation-specific PCR. Kaplan-Meier curves and log-rank tests were used to estimate cause-specific survival. Hazard ratios and corresponding 95% confidence intervals were assessed using Cox proportional hazard models. To assess the predictive capacity and fit of models combining several methylation markers, Harrell's C statistic and the Akaike Information Criterion were used.
We identified four methylation markers, i.e. GREM1, NEURL, LAD1 and NEFH, that individually predicted prognosis of ccRCC patients. The four markers combined were associated with poorer survival in two independent patient series (HR 3.64, 95% CI 1.02-13.00 and HR 7.54, 95% CI 2.68-21.19). These findings were confirmed in a third series of ccRCC cases from The Cancer Genome Atlas (HR 3.60, 95% CI 2.02-6.40).
A four-gene promoter methylation marker panel consisting of GREM1, NEURL, LAD1 and NEFH predicts outcome of ccRCC patients and might be used to improve current prognostic models.
Clinical cancer research : an official journal of the American Association for Cancer Research. 2016 Oct 18 [Epub ahead of print]
Iris J H van Vlodrop, Sophie C Joosten, Tim de Meyer, Kim M Smits, Leander Van Neste, Veerle Melotte, Marcella Baldewijns, Leo J Schouten, Piet A van den Brandt, Jana Jeschke, Joo Mi Yi, Kornel Schuebel, Nita Ahuja, James G Herman, Maureen Aarts, Fred T Bosman, Wim Van Criekinge, Manon van Engeland
Pathology, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center., Medical Oncology, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center., Mathematical Modeling, Statistics and Bioinformatics, Ghent University., Pathology, Maastricht University Medical Centre., Pathology, Maastricht University Medical Center., Department of Pathology, Maastricht University Medical Center., Pathology, University Hospital Antwerp., School for Oncology and Developmental Biology (GROW), Department of Epidemiology, Maastricht University Medical Centre., Department of Epidemiology, GROW School for Oncology and Developmental Biology, Maastricht University., Laboratory of Cancer Epigenetics, Free University of Brussels (U.L.B)., Research Institute, DIRAMS., Neurogenetics, NIH/NIAAA., Department of Medical Oncology, Johns Hopkins University School of Medicine., Co-Director, Lung Cancer Program, University of Pittsburgh Cancer Institute The Hillman Cancer Center., Medical Oncology, Maastricht University Medical Center., Department of Pathology, University of Lausanne., Mathematical Modelling, Statistics and Bio-informatics, Ghent University., Pathology, Maastricht University Medical Center .