['Expression of disaccharidase sucrase-isomaltase (SI) is significantly enhanced during neoplastic transformation of colonic epithelium. Our study was designed to determine whether expression of SI within primary tumors was significantly associated with survival in patients with colorectal carcinoma (CRC).', 'SI expression was analyzed by immunohistochemistry in paraffin sections from 182 Stage I to III CRC that had been resected for cure at the New England Deaconess Hospital between 1965 and 1977. Expression was scored as absent or present in 1 to 50 percent or more than 50 percent of tumor cells. Associations were explored among SI expression, other clinical or pathologic variables, and overall survival. The data set is mature, with 91 (56 percent) patients who had died of CRC at a median follow-up of 96 months.', 'Fifty-five percent of primary CRC expressed SI. When the multivariate Cox analysis was performed, nodal status, T stage, primary site, grade, and SI expression were independent covariates. SI expression was not associated with the expression of other clinicopathologic variables but increased the risk of death from colorectal carcinoma by 1.83-fold.'] Is sucrase-isomaltase an independent prognostic marker for colorectal carcinoma?