Several genes in breast cancer exhibit CpG island hypermethylation (53) and in several instances, abnormal activity of DNA methyltransferases led to the hypermethylation and silencing of HOXA5, TMS1, p16, RASSF1A, and BRCA1 genes of tumor suppressor behavior (54–56). The gene discussed is CDKN2A; the disease is breast carcinoma.