CDKN2A and ulcerative colitis: Colorectal inflammation, as one of the major risk factors of colorectal cancer, was found to be tightly connected to p16INK4a methylation: Wang et al. detected hypermethylation in the promoter region of p16 in human colonoscopic biopsies of rectal inflammatory mucosa, while Hsieh and colleagues suggested the hypermethylation of the p16INK4a promoter region to occur early during the neoplastic progression of ulcerative colitis in colectomy specimens [122,124].