Low Claudin-1 Expression Has Association with Deep Invading and Higher-Grade Colorectal Adenocarcinoma

Background Claudin-1 is a tight junction protein in the cell that organizes paracellular permeability and epithelial polarity and maintains apical cell-to-cell adhesion. Deregulation of claudin-1 homeostasis will play a pivotal role in tumorigenesis, migration, and metastasis of colorectal cancer through a complex signaling pathway. This study investigated the association of claudin-1 expression and clinicopathological factors in colorectal adenocarcinoma. Methods This study was a cross-sectional study of 43 colorectal cancer patients. Each clinicopathological parameter data was divided into 2 categories; depth of tumor invasion (T3, T4), degree of tumor differentiation (low, high grade), tumor location (right, left), sex (man, woman) and age (<60, ?60 y.o). Claudin-1 expression was examined by the immunohistochemistry method and evaluated by the H-Score method. The H-score cut off was determined by the mean value of 148. The difference of claudin-1 expression score with tumor depth invasion and age was analyzed by Independent t-test, and then the degree of differentiation, tumor location, and sex were analyzed by Mann-Whitney. All variables were analyzed by the Chi-square analysis with a significance value of P<.05. Results There was a significant mean difference of claudin-1 expression between T3 and T4 tumors (P=.041; 95% CI 1.7-75.1). Tumor with low expression of claudin-1 was 2.5 times more likely to be found in tumors with invasion depth T4 rather than T3 (P=.023; 95% CI 1.5-48). In addition, tumor with low expression of claudin-1 was 0.2 times more likely to be found in the high-grade tumor (P=.001; 95% CI 0.07-0.4). Claudin-1 expression was not statistically significant in different tumor locations, sex, and age group. Conclusion There was a mean difference in claudin-1 expression between T3 and T4 tumors and between low- and high-grade tumors. The low claudin-1 expression is associated with tumor depth invasion and poorly differentiated tumors. Therefore, the use of claudin-1 as an additional prognostic factor in colorectal cancer is proposed.