Nimesulide (4-nitro-2-phenoxymethanesulfonanilide), a selective inhibitor of COX-2, belonging to the sulfonamide class [9], is less ulcerogenic than other NSAIDs [10], and suppresses the formation of aberrant crypt foci (ACF), being putative precancerous lesions of the colon cancer, induced by a colon carcinogen, azoxymethane (AOM) in rats [11]. The gene discussed is PTGS2; the disease is malignant colon neoplasm.