Evaluation of clinical significance of claudin 7 and construction of prognostic grading system for stage II colorectal cancer.

Abstract

Claudin 7 is often abnormally expressed in cancers and promotes the progression of some malignancies. However, the role of claudin 7 in stage II colorectal cancer (CRC) has not been studied. To assess the expression and prognostic value of claudin 7 in stage II CRC. We retrospectively studied 231 stage II CRC patients who underwent radical surgery at our hospital from 2013 to 2014. The protein expression level of claudin 7 was assessed and its relationship with clinicopathological features and prognosis was statistically analyzed. The independent prognostic factors were identified by Cox proportional hazards models. A prognostic grading system was constructed to stratify the survival of CRC patients. The expression of claudin 7 was significantly reduced in cancer tissues compared with normal tissues (P < 0.001), and its low expression was closely related to recurrence of the disease (P = 0.017). Multivariate analysis confirmed that claudin 7 low expression (claudin 7-low) (P = 0.028) and perineural invasion positivity (PNI+) (P = 0.026) were independent predictors of poor disease-free survival (DFS). A prognostic grading system based on the status of claudin 7 and PNI classified the patients into three prognostic grades: grade A (claudin 7-high and PNI-), grade B (claudin 7-low and PNI-, claudin 7-high and PNI+), and grade C (claudin 7-low and PNI+). The DFS was significantly different among the three grades (grade B vs grade A, P = 0.032; grade C vs grade A, P < 0.001; grade C vs grade B, P = 0.040). Claudin 7 can be used as a new prognostic marker to predict the DFS of patients with stage II CRC. The prognostic grading system with the addition of claudin 7 can further improve prognosis stratification of patients.