The expression patterns of tight junction protein claudin-1, -3, and -4 in human gastric neoplasms and adjacent non-neoplastic tissues

Recently, there is growing evidence that tight junction proteins are often abnormally regulated in human tumors. The function of tight junction proteins in the maintenance of normal epithelial physiology has been well discussed, but their role in the tumorigenesis of gastric cancer is less well defined. To explore the expression distinction of the tight junction proteins claudin-1, -3, and -4 expression in the gastric cancer, the expression of claudin-1, -3, and -4 in 92 gastric cancer tissues and the non-neoplastic tissues adjacent to the tumors were examined by immunohistochemistry. Compared with adjacent non-neoplastic tissues, the expression of claudin-1 was down regulated. However, the expression of claudin-3 and claudin-4 were up-regulated in gastric cancer tissue. In addition, the expression of claudin-3 is correlated with claudin-4 expression in gastric cancer. Our present study reveals that claudin-1, -3, and -4 protein expression altered between human gastric cancers and adjacent non-neoplastic tissues.