A, Experimental scheme for the AOM/DSS-induced colon carcinogenesis model. C57Bl/6J mice provided water (Control) or water containing sildenafil (5.7mg/kg/day). B, Change in body weight from the initial weight. AOM was administered on day 0, and grey panels depict DSS treatment cycles. C, Representative colons from AOM/DSS treated mice, top-bottom orientation is proximal-rectal and representative polyps are indicated in the first panels by arrows. D, Plot shows the effect of sildenafil on median polyp number per animal (n=14 per group). Asterisks show difference between weight loss between treated and control groups at each day, p < 0.0001; Panel D, p-value generated with Mann–Whitney test.