TP53INP1 and melanoma: Four genes: PPP1R3C (protein phosphatase 1, regulatory (inhibitor) subunit 3C), ENC1 (ectodermal-neural cortex 1), RARRES1 (retinoic acid receptor responder also known as tazarotene induced gene 1, TIG1) and TP53INP1 (tumor protein p53 inducible nuclear protein 1), had mRNA levels that were inversely correlated with promoter methylation (>40–60% of CpG sites) in 35–59% of melanoma cell lines and 6–25% of the fresh tumors.