Nitric oxide (NO)-aspirin, a nitric oxide releasing prodrug of aspirin, inhibits the catalytic activity of nitric oxide synthase (NOS)-2, along with two COX-2, as well as down regulated expression of β-catenin and proliferating cell nuclear antigen (PCNA) in colon tumors induced by azoxymethane [29]. Here, NOS2 is linked to colonic neoplasm.