Expression of CLDN6 in tissues of gastric cancer patients: Association with clinical pathology and prognosis

Expression of claudin-6 (CLDN6) in the tissues of gastric cancer patients and its association with clinical pathology and prognosis were investigated. A retrospective analysis was performed on 213 gastric cancer patients diagnosed and surgically treated in the Central Hospital of Zibo from January 2010 to January 2013. Cancer and normal adjacent tissues were obtained from the patients to detect the expression level of CLDN6 using reverse transcription-quantitative PCR (RT-qPCR). The association between the expression level of CLDN6 and the clinical and pathological features, as well as the prognosis of gastric cancer patients was analyzed. The expression level of CLDN6 was significantly lower in gastric cancer tissues than that in adjacent tissues (t=23.350, P<0.001). The expression level of CLDN6 was associated with age, lymph node metastasis, pathological staging, and distant metastasis (P<0.05). In this study, patients were separated into CLDN6 high-expression group (≥1.42) with 107 patients and CLDN6 low-expression group (<1.42) with 106 patients, with the median expression level of CLDN6 as the boundary. The 1-, 2- and 3-year survival rates of patients in the CLDN6 low-expression group were 80.19, 60.38 and 48.11%, respectively, and those in the CLDN6 high-expression group were 87.85, 73.83 and 66.36%, respectively. The survival rate was significantly better in the CLDN6 high-expression group than that in the CLDN6 low-expression group (P=0.009). In conclusion, the expression level of CLDN6 is low in the cancer tissues of gastric cancer patients, and associated with age, lymph node metastasis, pathological staging and distant metastasis. CLDN6 low expression has a certain negative impact on the prognosis of patients, and therefore, shows potential as an important indicator for the prognosis of gastric cancer patients.