Clinical Implications of Claudin18.2 Expression in Patients With Gastric Cancer.

Background/Aim: Claudin18.2 (CLDN18.2) is a tight junction protein that has been identified as a promising target in gastric cancer. This study aimed to evaluate the clinical relevance of CLDN18.2 expression in gastric cancer. Patients and Methods: This study included 367 patients diagnosed with gastric cancer, who underwent curative surgical resection. Immunohistochemical staining for CLDN18.2 was carried out, and expression was scored semi-quantitatively, based on staining intensity and the percentage of staining. Results: CLDN18.2 expression was observed in 273 patients (74.4%), and 108 (29.4%) were classified as CLDN18.2-positive by predefined criteria. CLDN18.2 expression was not correlated with age, sex, tumor location, or stage. Expression rates were higher in diffuse-type and HER2-positive tumors. In multivariate survival analysis, CLDN18.2 expression was not associated with survival outcomes. Conclusion: Higher expression of CLDN18.2 was observed in diffuse-type and HER2-positive gastric cancers. Meanwhile, CLDN18.2 expression was not associated with survival in patients with gastric cancer.