NOS2 and carcinoma: Of all the modes of human colorectal cancer induction (e.g., adenoma-carcinoma sequence or chromosomal instability pathway, hereditary nonpolyposis colon cancer or HNPCC, and colitis-associated), colitis-induced colorectal cancer (CAC) is unique in its pathophysiology, involving inducible nitric oxide synthase (iNOS)-mediated free radical injury in the setting of a persistently inflamed mucosa [6].