RARRES1 and Familial prostate cancer: While a hypermethylation-associated downregulation of RARRES1 was observed in several cancers, such as prostate cancer, nasopharyngeal carcinoma, melanoma, and colorectal adenocarcinoma, pointing to a role as a tumor suppressor, RARRES1 expression has been considered an unfavorable prognostic factor in renal cancer and glioma being associated with mesenchymal subtypes [23,26,28,29,30,31].