TP53 and melanoma: For example, T-cell ALL was modeled by transgene-driven expression of the MYC oncogene using the rag2 promoter, and melanomas generated by expressing BRAFV600E under the mitfa promoter in a tp53−/− germline mutant background (Berghmans et al., 2005; Langenau et al., 2003; Patton et al., 2005).