Relationship of the tight junction protein claudin-4 gene to outcomes in patients with colorectal cancer

Abstract

Background: The tight junction protein claudin is abnormally regulated in several human cancers. In particular, claudin-4 is frequently overexpressed in several neoplasias, including breast, pancreatic, ovarian, and prostate cancers. This study examined the relationship of the relative expression of the claudin-4 gene to the clinicopathological factors and outcomes in patients with colorectal cancer (CRC). Methods: We studied surgical specimens of cancer tissue and adjacent normal mucosa obtained from 202 patients with untreated CRC. The relative expression of claudin-4 mRNA in cancer and in normal adjacent mucosa was measured by quantitative real-time reverse-transcriptase polymerase chain reaction. Results: The claudin-4 expression was higher in cancer tissue than in adjacent normal mucosa. The claudin-4 expression was related to the cancer location. The overall survival at five years differed significantly between patients with a high claudin-4 expression and those with a low expression. Conclusion: The overexpression of claudin-4 was considered a useful predictor of outcomes in patients with CRC.