MUC1 core protein as a marker of gallbladder malignancy

Aim The significance of MUC1 expression in the gallbladder tissues in relation to cancer and non-cancer disease is not well understood. The aim of this study was to clarify the significance of MUC1 expression. Materials and methods A monoclonal antibody (CA 15-3; DF3) was applied to stain MUC1 core protein in surgical specimens. Results MUC1 expression is significantly higher (p<0.0001) in gallbladder cancer (69/88) compare to non-cancerous tissue, while, very trace in normal and inflammatory tissues. The expression rate was significantly lower (p<0.0001) when the cancer did not penetrate the mucosal layer than when cancers did penetrate this layer. The MUC1 expression rate was (4/14) in T1 tumours, (11/14) in T4, (40/45) in T3, and (14/15) in T2, respectively. Every cell of normal and inflammatory mucosa, and T1 cancers had the polarized pattern. The depolarized pattern was dominant in cancer cells from the advanced tumours of T2, T3 and T4. That is, (45/74) of cancer cells from the mucosal layer and (58/74) of penetrating cancer cells in submucosal layer had the depolarized pattern. There was no significant correlation of MUC1 expression rate and staining pattern with cancer differentiation and microscopic venous invasion. On the other hand, lymphatic vessel invasion was significantly correlated with the staining pattern but not with expression rate. Conclusion MUC1 core protein expression rate and pattern are suggesting that MUC1 core protein would be a marker of malignant transformation of gallbladder epithelium and its depolarized expression would also be a marker of invasion of gallbladder cancer.