CD274 and gastric cancer: Through the regulatory mechanism of ceRNA, upregulated SNHG15 positively promotes the expression of PD-L1 on the surface of dendritic cells, macrophages, or gastric cancer cells in gastric cancer tissues, induces apoptosis, non-response, and dysfunction of T cells, and eventually leads to an increase in the immune escape activity of gastric cancer cells and promotes immunotherapy resistance [139].