APC and neoplasm: This was accompanied by promoter demethylation and re-expression of four tumor suppressor genes, including ATM (ataxia telangiectasia mutated, an important cell cycle checkpoint kinase), APC (adenomatous polyposis coli, an antagonist of the Wnt-signaling pathway), the phosphatase PTEN, and SERPINB5 (mammary serine protease inhibitor encoding the Maspin protein) [69].