CTLA4 and gastric cancer: Currently, immunotherapies based on blockade of immune checkpoints (such as CTLA-4 31, PD1, and PD-L1) receptors and their ligands have made considerable progress not only in Gastric cancer but also in colon, lung, and renal carcinoma.16 However, effective biomarkers for prognosis predicting and selecting patients sensitive to immunotherapy and can benefit from the therapy the best remains unclear.