DF3 expression in human gallbladder carcinoma: significance for lymphatic invasion

DF3 (MUC 1) is a member of a family of high molecular weight glycoproteins. Recent studies have demonstrated that DF3 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. However, expression patterns of DF3 have not yet been established in human gallbladder carcinomas. In this study, we examined DF3 expression in human gallbladder adenocarcinoma and its clinicopathological significance. DF3 immunoreactivity was detected not only in the cancer cells (cytoplasmic type; 50.0%, 27/54) but also in the cancer stroma (stromal type; 46.3%, 25/54). According to TNM classification, 65.0% (26/40) of T2-4 gallbladder cancers showed cytoplasmic DF3, while 7.1% (1/14) of the T1 cancers were cytoplasmic DF3-positive (p<0.001). Stromal DF3 expression was detected in 62.5% (25/40) and none (0/14) of the T2-4 and T1 cancers, respectively (p<0.001). Lymph node metastasis was frequently found in the cytoplasmic DF3- and stromal DF3-positive gallbladder cancers (59.3% and 60.0%, respectively). These observations suggested that DF3 expression plays important roles in cancer cell growth and metastasis of human gallbladder adenocarcinomas.