Correlation between expression of MUC1 core protein and outcome after surgery in mass-forming intrahepatic cholangiocarcinoma

BACKGROUND. It has been reported that MUC1 is an important prognostic factor in several cancers. This study investigated the importance of MUC1 as a prognostic factor in mass-forming intrahepatic cholangiocarcinoma (m-ICC). METHODS. In 50 patients with m-ICC who had undergone hepatectomy, expression of MUC1 was investigated. Expression of MUC1 was examined by immunohistochemical staining with monoclonal antibody HMPV, which recognizes the MUC1 core peptide. The immunohistochemical staining patterns of MUC1 were classified into three types: ductal type (the luminal surface membrane of neoplastic cells was stained), cytoplasmic type (the cytoplasm of neoplastic cells was stained dominantly), and negative type. RESULTS. Expression of MUC1 was detected immunohistochemically in 38 (76%) of 50 cases of m-ICC (ductal type, 18; cytoplasmic type, 20; and negative type, 12). Seventy-five percent of patients with lymph node metastasis had the cytoplasmic type MUC1 expression. Lymph node dissection was performed in only 20 patients, but significant correlation was demonstrated between MUC1 expression and lymph node metastasis (P = 0.0227). The location of MUC1 expression correlated with surgical outcome in m-ICC. Patients with the cytoplasmic type expression showed significantly lower survival rates. Univariate analysis revealed that MUC1 expression was a statistically significant risk factor affecting outcome in m-ICC (P = 0.0028). Furthermore, expression of MUC1 was found to be a statistically significant independent risk factor in multivariate analysis (P = 0.0063). CONCLUSIONS. The results suggest that evaluation of MUC1 expression may be very useful in predicting the surgical outcome in m-ICC. (C) 2002 American Cancer Society