CDKN2A and cancer: However, subsequent studies (Kazianis et al., 1999, 2000) revealed that CDKN2X was hypomethylated and overexpressed in melanized skin and melanomas, an unexpected characteristic based on the role of CDKN2A in human melanoma as currently understood (Ruas and Peters, 1998), although CDKN2A is overexpressed in some other human cancers.