Prognostic significance of Claudin18.2 expression in patients with gastric cancer: Insights from original research and meta-analysis

Background: Claudin 18.2 (CLDN18.2) is a novel treatment target for patients with unresectable or stage IV gastric cancer. However, it remains unclear whether the expression of CLDN18.2 affects survival outcomes. Methods: In total, 586 patients with GC were enrolled in this study. CLDN18.2 expression in cancer cells was analyzed by immunohistochemistry. Correlations between CLDN18.2 expression and several clinicopathological factors and survival outcomes were investigated. We also performed a systematic review and a meta-analysis. Results: CLDN18.2expression was mainly observed in the cell membrane. The CLDN18.2 expression was not significantly correlated with any clinicopathological factor. In all patients, CLDN18.2 did not significantly affect OS. In patients with the diffuse type, the overall survival of patients with CLDN18.2-high expression was worse than that of patients with CLDN18.2-lowexpression, although the difference was not significant (p=0.092). Meta-analyses revealed that CLDN18.2 was not significant prognostic factor in resected cases, although CLDN18.2 negative cases showed a trend for worse survival. Conclusion: CLDN18.2 was not a significant prognostic factor in general, although CLDN18.2 negative cases showed a trend for worse survival. We revealed that patients with CLDN18.2 high expression showed worse survival outcomes especially in the diffuse type.