PTEN and melanoma: We combined this mutant Prex2E22A,N204A (Prex2gd) allele with our BRAF PTEN melanoma model (Tyr-CreERT2BrafV600E/+Ptenfl/+Prex2gd/gd – BRAF PTEN PREX2-GD; Supplementary Figs. S2D and S3).