CDK4 and melanoma: Concerning the germline genetic background of melanoma, genetic screening aims to identify either variants of predisposing genes with high penetrance (CDKN2A, CDK4, BAP1, POT1, ACD, TERF2IP, and TERT) or variants of susceptibility genes with medium or low penetrance (MC1R, MITF, SLC45A2, TYR, OCA2, ASIP, PL2G6, FTO, PARP1, ATM, CDKAL1, CCND1, and CYP1B1), which are known to play a major role in the genetic background of melanoma [1,5].