Patients with depressive symptoms in GC have increased levels of reactive oxygen species in their bodies, which can activate the phosphatidylinositol 3−kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) signaling pathway to suppress the maturation of dendritic cells(DC), reduce (TILs), and promote the proliferation of immunosuppressive myeloid-derived suppressor cells, thereby reducing the effectiveness of ICIs (45–47). The gene discussed is MTOR; the disease is gastric cancer.