Claudin-18 Status and Its Correlation with HER2 and PD-L1 Expression in Gastric Cancer with Peritoneal Dissemination

Gastric cancer with peritoneal dissemination (PD) has a dismal prognosis, and current treatments have shown little efficacy. CLDN18.2-targeted therapies have shown promising efficacy against gastric cancers that express high levels of CLDN18. Because of the limited information regarding CLDN18.2 status in PD, we analyzed PD-positive gastric cancers for CLDN18 status in both primary and PD, along with HER2 and PD-L1 combined positive score (CPS). Immunohistochemical analyses were performed on 84 gastric cancer cases using paired primary and PD tissue samples. At 40