CDKN2A and colorectal neoplasm: Large-scale DNA hypomethylation usually associates with genomic instability, while locus-specific hypermethylation in tumor cells usually corresponds to silenced transcription of tumor suppressor genes [2–4], for example, due to the promoter hypermethylation, OVOL2 (ovo like zinc finger 2), MLH1 and CDKN2A (p16/ARF) were silenced in colorectal tumors [5–7], BRCA1 was silenced in ovarian cancer [8] and breast cancer [9].