['Immunohistochemical evaluation of p53 staining patterns has been considered as a complementary test for dysplasia in ulcerative colitis-related colorectal cancer surveillance, but usefulness would be particularly important if it were a marker associated with a poor prognosis. The aim of this study was to determine whether abnormal p53 staining of the tumor correlated with cancer-related mortality in ulcerative colitis patients.', 'An historical cohort study was designed to examine all ulcerative colitis patients who developed colorectal cancer between 1978 and 1997 and who had tumor tissue blocks available for staining. Tissue was recut and stained for abnormal p53 immunohistochemistry using the DO-7 antibody. Tumors were considered to be p53 positive if at least 5% of nuclei in a high power field were positive for staining.', 'Among 75 patients entered in the study, 38 (50.7%) had p53 positive tumors. Fourteen patients (36.8%) with p53 positive tumors died from colorectal cancer, compared to five (13.5%) with p53 negative tumors (p < 0.04, log-rank test). The adjusted relative risk of cancer-related death among patients with p53 positive tumors was 3.03 (95% CI = 1.05-8.73).'] Is abnormal p53 immunohistochemistry associated with an increased colorectal cancer-related mortality in patients with ulcerative colitis?