However, the pooled results of three studies with 473 patients failed to show the significant association of claudin-4 with distant metastasis of gastric cancer (OR: 1.10, 95 % CI: 10.70–1.74, P = 0.067), and there was no significant heterogeneity among the studies (I2 = 0.0, P = 0.851). This evidence concerns the gene CLDN4 and gastric cancer.