XPC and urinary bladder carcinoma: A variable impact of factors such as cigarette smoking have been correlated to XPC expression in bladder cancers, and more recently, studies have suggested a role of both promoter hypermethylation and histone deacetylation by HDACs in regulation of XPC mRNA expression in bladder cancer (138, 139), the latter of which is supported by previously studies reporting SIRT-1 deacetylase regulation of XPC expression in other (skin) cancers (140).