CDK4 and metastatic melanoma: For example, a significant number of genes were involved in G1/S cell cycle transition and in p53-dependent apoptosis (Table 1; MetaCoreTM analysis, p<0.01), including p14ARF, p16INK4A and p15INK4B, which were deleted as part of the recurrent 9p21 locus deletion, as well as CDK4 and MDM2, both of which were recurrently amplified in metastatic melanoma (Supplemental Figure S3).