CDKN2A and melanoma: Conversely, the prevalence of CDKN2A alterations (19/32; 59.4%)—which include inactivating gene mutations, exon deletions, and amino acid substitutions—was much higher in cell lines derived from melanoma metastases (16/24; 66.7%) than in those derived from primary melanomas (3/8; 37.5%) (Table 1).