PTEN and melanoma: In addition to focal DNA hypermethylation of the well-investigated tumor suppressor genes PTEN, CDKN2A (p16/p14), and RASSF1A, with promoter hypermethylation prevalence of 6–62% (PTEN), 5–27% (p16), 41–57% (p14), and 15–57% (RASSF1A), respectively [36], focal hypermethylation of many more genes has been reported in melanomas.