Expression of MUC2 and MUC6 in Colorectal Adenomas and Adenocarcinomas

Park, Ho Sung; Kong, Tae Shik; Jang, Kyu Yun; Chung, Myoung Ja; Moon, Woo Sung; Lee, Dong Geun; Kang, Myoung Jae

Abstract

PURPOSE: Although the expression of MUC2 is seen in colorectal tumors, there have been few reports about the expression of MUC6 in colorectal tumors. The aim of this study was to investigate the expressions of MUC2 and MUC6 in normal colorectal tissues and in tumors, as well as the association of MUC2 and MUC6 expressions with prognostic factors.
METHODS
Twenty (20) cases of colorectal adenomas treated by using a endoscopic polypectomy and 30 cases of colorectal carcinomas treated by using a resection were collected. Ten (10) normal tissue samples were obtained apart from the carcinomas. Sections were used for MUC2 and MUC6 immunostaining. The expressions of MUC2 and MUC6 were scored by using the sum of the percentages of the stained cells and the intensity of staining.
RESULTS
All of the ten normal colorectal tissues expressed MUC2 and MUC6. Of the 20 adenomas, 19 cases (95%) were MUC2 positive, and 17 cases (85%) were MUC6 positive. Adenomas with severe atypia tended to express lower levels of MUC2 and MUC6 than those with mild or moderate atypia. Of the 30 carcinomas, 28 cases (93%) were MUC2 positive and 19 cases (63.3%) were MUC6 positive. Colorectal mucinous carcinomas differed significantly from non-mucinous carcinomas in strong MUC6 expression. MUC2 expression showed a significant association with lymph-node metastasis.
CONCLUSIONS
The results suggest that MUC6 is expressed in normal colorectal tissues and tumors, that MUC6 expression is especially strong in mucinous carcinomas, and that MUC2 expression is associated with lymph-node metastasis, among the prognostic factors.