CD274 and neoplasm: Some studies showed that PD-L1+ GISTs have more immune cells infiltration [103, 105, 125], and PD-L1 expression in GIST was negatively correlated with tumor size [98, 103], mitotic index [103], high risk GISTs [152] and metastasis [152], and was positively correlated with improved RFS [103], suggesting that high PD-L1 expression is associated with antitumor immune response and better prognosis.