TYR and melanoma: The inducible Cre recombinase under the Tyrosinase promoter is induced by 4-hydroxytamoxifen and drives expression of the BrafV600E oncogene, the most common mutation found in human melanoma patients, combined with a homozygous loss of the tumor suppressor gene Pten. As observed in the Tyr::NrasQ61KInk4a−/− mouse model, the overall survival in the BrafV600EPten−/−Tyr::CreERT2 was also prolonged significantly in the CHIR99021 treated group compared with the control group (Fig. 6i, j).