CpG island hypermethylation of corticotropin-releasing hormone-binding protein in kidney cancer and association with clinicopathological parameters.

Abstract

414 Background: Significance of Urocortin (Ucn or UcnI), Ucn2, Ucn3, and their receptors, Corticotropin Releasing Factor Receptor 1 and 2 (CRFR1 and CRFR2), and the binding protein, Corticotropin-Releasing Hormone-Binding Protein (CRHBP) in oncology is growing rapidly. Recently we found that the UCN system may also be a relevant structure in renal cell cancer. Here we investigate whether CRHBP CGI methylation occurs in cc-RCC and whether its methylation is associated with clinicopathological parameters of patients. Methods: Tumoral tissues of 109 patients with renal cell cancer and their corresponding normal tissues have been used. Combined bisulfite restriction analysis (COBRA) for detection of relative degree of CpG island (CGI) methylation and pyrosequencing have been performed. Results: We found an approximately five-fold increase in mean methylation of the CRHBP CGI for tumor tissues (p < 0.00005). Higher DNA methylation of the CRHBP CGI showed a positive correlation with advanced disease as well (p = 0.024). Conclusions: To our knowledge we report for the first time the CGI methylation of CRHBP in clear cell renal cell carcinoma indicating a contribution of epigenetic alteration of CRHBP to RCC tumorigenesis. Moreover, our results suggest CRHBP as a potential molecular marker for assessment of progression and aggressiveness of tumors.