Altered expression of MUC2, MUC4, and MUC5 mucin genes in pancreas tissues and cancer cell lines

Background/Aims: Neoplastic transformation of epithelial cells is commonly associated with altered synthesis and structure of mucin glycoproteins. The aim of the study was to determine if altered mucin gene expression takes place in pancreas cancer. Methods: To examine mucin gene expression in normal pancreas and pancreas cancer, antibodies detecting the MUC1, MUC2, MUC5B, and MUC5C apomucins were used in immunohistochemical techniques and complementary DNA probes specific for the MUC1-MUC5 genes were used in Northern blots. Results: MUC1 is the major apomucin expressed in normal pancreas, whereas MUC2-MUC5 are weakly expressed or undetectable. In pancreas cancer tissues and cell lines, increased expression of MUC2, MUC4, and MUC5C is shown. The cytoplasmic expression of MUC2 and MUC5C in tumor cells suggests that these apomucins are underglycosylated and abnormally compartmentalized. Conclusions: Enhanced expression of MUC2, MUC4, and MUC5C genes is a frequent event in pancreas cancer and may contribute to the alterations in the biochemical structure of pancreas cancer mucins.