This meta-analysis assessed the association between claudin-1 and prognosis, and the results showed that the high-expressed claudin-1 is correlated with lower aggressive tumor behavior and better prognosis (OS: HR, 0.46; 95% CI, 0.28–0.76; P = 0.002; DFS: HR, 0.44; 95% CI, 0.29–0.65; P < 0.0001). This evidence concerns the gene CLDN1 and neoplasm.