Gastric carcinoma is one of the most frequent malignant tumors in the world. The gastric carcinoma cell with fibroblastic pattern which intracellular adhesion was decreased showed active mobility and invasiveness，which indicated that the EMT was placed. The TJ protein participated in EMT of tumors. Four transmembrane proteins of claudin family were essential component of TJ, but the effect of the TJ protein in the development of cancers was not clarified, especially the effect of claudin-1 expression transformation in gastric carcinomas.
A research article to be published on August 21, 2008 in the World Journal of Gastroenterology addresses this question. The research team led by Professor Zhang from Dept. of Pathology in the First Affiliated Hospital of Fujian Medical University used immunohistochemistry to study the expression of claudin-1 and the relationship between the expression transformation of claudin-1 and the biological behavior in the gastric carcinomas.
The positive relationship between the over-expression of claudin-1 and the invasiveness and metastasis was found. The expression transformation of claudin-1 with the invasiveness and metastasis was found in the gastric carcinoma. Compared with the claudin-1 expression in the areas of mucosa, the expression of claudin-1 in the areas of the invasive front was transformed in 28/136 gastric carcinoma, in which the expression of claudin-1 was transformed from low to high. The transformed rate of claudin-1 expression significantly related with the degree of differentiation and the depth of the invasiveness in gastric carcinomas. However, the mechanism of claudin-1 expression transformation was unclear and need to further study.
The discovery in this study is mainly the positive relationship between expression transformation of claudin-1 and biological behavior in gastric carcinomas. These results demonstrate up-regulation and transformation of claudin expression in the invasiveness process of gastric carcinomas involves in biological behavior transformation of tumors and TJ protein participated in process of the EMT and MET, and thus may provide a new idea for further understanding of the biological function of TJ protein in cancers.