CDKN1A and neoplasm: Mutation of BRAF (like BRAFV600E) in melanocytic cells leads first to cell proliferation, followed by growth arrest, induction of tumor suppressors including p16INK4A and p21CIP1 (p21SDI1, p21WAF1, gene CDKN1), and SA β-gal expression, as senescence markers in nevi [10,11].