MUC1 Expression in Colorectal Cancer is Associated with Malignant Clinicopathological Factors

This study aimed to evaluate the frequency, distribution, and corresponding histology of MUC1 expression in colorectal cancer and examine its association with clinicopathological factors. MUC1 expression was con rmed in 86 of 169 surgically resected colorectal cancers (51%), although the ratio of MUC1-positive cells was less than 5% in 33 cases (20%), 5-50% in 46 cases (27%), and greater than 50% in only 7 cases (4%). None or less than 5% of MUC1 expression cases were classi ed as L-group cancers (116 cases, 69%), while cancers showing higher than 5% expression were classi ed into the H-group (53 cases, 31%). Analysis of the intratumoral distribution of positive cells in the H-group cases showed MUC1 expression distributed predominantly in the upper layers in 3 cases (6%), in the lower layers in 18 cases (34%), and in all layers in 32 cases (60%). MUC1 expression was observed in various histomorphological cancer forms, but the most frequent expression was noted in the monolayer cuboidal (pancreatobiliary-type) neoplastic glands. Considering the relationship between MUC1 expression and clinicopathological factors, H-group cases demonstrated signi cantly larger lesions showing a greater number of ulcerated-type cancers, deeper invasion, poorer differentiation, higher frequency of budding, and higher rate of lymph node metastasis than L-group cancers. Furthermore, there was a difference of 10% between the H-group and L-group with regard to the frequency of relapse/tumor mortality three years after surgery. In colorectal cancer, MUC1 expression increases with progression of the tumor indicating that it is one of the useful indicators of malignancy and may facilitate appropriate treatment regimens ; however, as its expression is heterogeneous and localized, it will be necessary to con rm the state of MUC1 expression by case.