MUC1 and MUC2 expression in human gallbladder carcinoma: a clinicopathological study and relationship with prognosis.

Mucins are a group of high molecular weight glycoproteins consisting of a mucin core protein and O-linked carbohydrates. To date, nine apomucins (MUC1-8, and MUC5B) have been identified. Recent studies have demonstrated that MUC1 is expressed in tumors of various human organs, and may function as an anti-adhesion molecule that inhibits cell-to-cell adhesion, inducing tumor metastasis. MUC2 is a major secreted mucin of colon and is known to be expressed in cells showing intestinal metaplasia in the stomach and other organs. MUC2 expression in the mucosal epithelia is an apparently abnormal phenomenon related to the neoplastic process. In this study, we examined MUC1 and MUC2 expression in human gallbladder adenocarcinoma and its clinicopathological significance and relationship with the prognosis of the patients. MUC1 immunoreactivity was detected not only in the cancer cells but also in the cancer stroma. Cytoplasmic MUC1 expression was significantly relation to lymphatic invasion and lymph node metastasis (p < 0.001), and was associated with a poor outcome. In contrast, MUC2 was rarely expressed in gallbladder carcinomas, and its immunoreactivity was detected only in the cancer goblet cells. Overexpression of MUC2 was not significantly related to lymphatic invasion or lymph node metastasis, or prognosis of patients. These observations suggested that MUC1 expression plays a more important role than MUC2 expression in cancer cell growth and metastasis of human gallbladder adenocarcinomas.