GPC3 and gastric cancer: In addition, GC patients with CAFs that highly express GPC3 exhibit a higher TIDE (Tumor Immune Dysfunction and Exclusion) score and respond poorly to PD-1 immunotherapy, which could be due to the fact that GPC3, secreted by CAFs, promotes the expression of the immune checkpoint genes, such as PD-L1, TIM3, and CD24, in GC cells [96].