Background: Colonic adenocarcinoma is the most frequent neoplasia of the intestine. This pathology is the third highest cause of death from cancer. The large majority of colorectal malignancies develop from an adenomatous polyp (adenoma). Estrogen receptor (ER)-β-induced inhibition of proliferation could be explained by the inhibition of the bcl-2 gene. ER-β protein levels are reportedly lower in colon tumors compared with normal colon tissue, and loss of ER-β is associated with advanced stages of colon cancer and tumor cell dedifferentiation, suggesting a protective role for ER-β in colon tumorigenesis.
Aim: The aim of the work was to assess the expression of ER-β in cases of colonic adenocarcinoma and adenomatous polyps, and its relation to tumorigenesis.
Materials and methods: Sixty archival formalin-fixed paraffin-embedded, routinely processed cases, constituting 40 cases of colonic adenocarcinoma and 20 cases of adenomatous polyps, were included in this study. For each selected case, clinical data were retrieved from the computer files.
Results: In this study, loss of ER-β expression was present in a larger number of adenocarcinoma cases (n=25) than in adenomatous polyps (n=5). ER-β expression showed a nonsignificant correlation between age and sex distribution in the studied cases of colonic adenocarcinoma and adenomatous polyps. ER-β expression showed significant correlation between the site and the size distribution in the studied cases of colonic adenocarcinoma and adenomatous polyps. ER-β expression is inversely proportional to the colonic adenocarcinoma stage and grade as the highest frequency of positive ER-β expression in the studied cases of colonic adenocarcinoma occurred in well-differentiated tumors (25%) and in modified Dukes’ stage B1 (20%) (P<0.05, significant).
Conclusion and recommendations: ER-β may protect normal colonic epithelial cells from undergoing unscheduled cell proliferation and neoplastic transformation. ER-β expression is related to tumorigenesis and prognostic factors in colonic adenocarcinoma. ER-β expression decreases in adenomas and colonic adenocarcinoma. Further studies are recommended to prove the protective effect of estrogen hormone replacement therapy against colonic adenocarcinoma in high-risk patients.