CDKN2A and neoplasm: Tumours in these mice develop p53 (ref. 25), RAS (ref. 26) and CDKN2A (ref. 27) mutations in similar proportions to those in human cuSCC, along with copy number variations that map to ones reported in human cuSCC (chromosomes 3p, 11p and 9q) (refs 28, 29, 30) Serial Analysis of Gene Expression (SAGE) mRNA gene expression data from this model, comparing UVR-induced cuSCC to NS epidermis, shows substantially similar patterns of changes to our human data including overexpression of matrix metalloproteinases and hyperproliferative keratins31.