Expression of tight junction proteins Claudin-1 in colorectal carcinoma and colorectal adenoma

Abstract

Objective Detecting the expression of Claudin-1 protein in the normal mucosa, colorectal adenoma with different pathological types and colorectal carcinoma with different stages and probing its meaning in different stages of colon carcinogenesis. Methods 80 colorectal adenoma samples of different pathological types resected endoscopically were collected, including 30 cases of tubular adenoma, 30 cases of tubular villous adenoma, and 20 cases of villous adenoma. Furthermore, the samples also included 60 cases of colorectal carcinoma specimens and 40 cases of paracancerous normal tissue specimens resected by general surgery. Immunohistochemistry was applied to detect the expression of Claudin-1 protein in the tissue samples. Results The positive rate of Claudin-1 expression in normal mucosa group, colorectal adenoma group and colorectal carcinoma group was 20.0%, 46.2% and 81.7% respectively, with the statistically significant difference (P=0.000). A significant rise in its expression from colorectal adenoma, to colorectal carcinoma gradually increased. And the expression of Claudin-1 was associated with the Dukes staging and the lymph node metastasis. The positive rate of Claudin-1 expression in tubular adenoma group, mixed pattern of adenoma group and villous adenoma group was 33.3%, 43.3% and 70.0% respectively, with significant differences among them (P=0.036). Conclusion The expression of Claudin-1 promotes the occurrence and development of colorectal carcinoma. The changes of Claudin-1 probably imply the occurrence of early colorectal carcinoma, and/or the malignant transformation risk of colorectal adenoma. Key words: Colorectal adenoma; Colorectal carcinoma; Immunohistochemistry; Tight junction proteins; Claudin-1