CLDN1 and neoplasm: Multivariate Cox regression analysis for RFS identified negative CLDN1 expression to be an independent adverse factor for tumor recurrence and death (HR 5.529, 95% CI 2.664–11.475, P<0.001; HR 3.459, 95% CI 1.555–7.696, P = 0.002) (Table 4, 5).