Furthermore, these two mouse tumors and the cell lines had either a deletion in exon 2 of the Ink4a/Arf gene or an interstitial deletion of the long arm of chromosome 4 (where the Ink4a/Arf gene resides), similar to genetic changes of human melanoma for CDKN2A, encoding p16INK4a and p19ARF [162]. This evidence concerns the gene CDKN2A and melanoma.