FAP and neoplasm: To further evaluate whether FAP+CAFs contribute to remodeling the tumor immune microenvironment and reducing the efficacy of anti-PD-1 therapy in gastric cancer, we isolated CAFs from gastric cancer tissues and upregulated FAP expression in CAFs cells through lentiviral vectors, establishing a cell line of FAP overexpressing CAFs derived from gastric cancer patients (FAP+CAFs) [Figure 2D].