CDKN2A and melanoma: In turn, constitutive activity of CDK4R24C overrides the ability of p16INK4A to function as a mediator of oncogene-induced senescence [20,21] A transgenic mouse strain engineered on a C57BL/6 genetic background for constitutive expression of CDK4R24C was shown to be prone to two step chemical (7,12-dimethylbenz[a]anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA))- and UV-induced melanomas, although the tumors exhibited little metastatic potential [21,22].