Association between sucrase-isomaltase and p53 expression in colorectal cancer

BACKGROUND

Sucrase-isomaltase (SI) is a tissue-based phenotypic marker that is an independent prognostic factor in colorectal cancer (CRC). DF3 and galectin 3 are two other tissue-based markers that are upregulated during neoplastic transformation. Because p53 mutations are acquired during neoplastic progression, we reasoned that alterations in SI and p53 may be associated despite an apparent lack of biological interaction.

METHODS

Paraffin sections from 183 patients who underwent surgery at New England Deaconess Hospital (NEDH) between 1965 and 1977 were analyzed first by immunohistochemistry (IHC) for the expression of the markers SI, DF3, and galectin 3, which were scored as absent or present. Paraffin sections from a second group of 59 patients who underwent surgery at NEDH between 1985 and 1992 were analyzed by IHC for the expression of p53 as well as SI, DF3, and galectin 3. p53 nuclear staining was scored as absent or present. Previous work has shown that p53 is mutated in all cells with nuclear staining and in 10% of tumors that are unstained.

RESULTS

SI expression was not associated with the expression of either DF3 or galectin 3, and neither DF3 nor galectin 3 were prognostic factors in CRC. None of the phenotypic markers were associated with any of the clinicopathologic variables. However, 21 of 24 p53-positive cases (88%) expressed SI, whereas 15 of 35 p53-negative cases (43%) were also SI negative (p = 0.02, Fisher exact test). p53 expression was not associated with expression of DF3 or galectin 3.

CONCLUSIONS

SI expression and p53 mutation are associated significantly in CRC. Although the mechanism underlying such an association in presently unknown, the association may define a subset of patients with a worse prognosis.

Sucrase-isomaltase is an independent prognostic marker for colorectal carcinoma

PURPOSE

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).

METHODS

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.

RESULTS

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.

DISCUSSION

These results indicate that SI is a prognostic marker for CRC that is independent of stage-related variables in patients who have undergone potentially curative resections.