CDKN2A and melanoma: Germline mutations in two genes, CDKN2A and (rarely) CDK4, have been shown to cause inherited melanoma susceptibility with high penetrance (Bishop et al, 2002; Hayward, 2003; Kefford and Mann, 2003), and a third such locus has recently been identified on chromosome 1p22 (Gillanders et al, 2003).