ERBB2 and gastric cancer: For all these reasons, in the present study, we investigated the immunohistochemical profile of CLDN18, and of other biomarkers that are in use in the clinical characterization of GC, such as p53, E-cadherin, MSH2, MSH6, MLH1, PMS2, HER2, EBER and PDL-1 combined positive score (CPS) in a large series of locally advanced or metastatic GCs (n = 280) and GECs (n = 70), focusing on the association of CLDN 18 expression with IHC results and survival outcomes.