CD274 and neoplasm: Biologically, chronic inflammation promotes tumor immune evasion and metastatic dissemination through synergistic effects, including activation of immunosuppressive pathways (e.g., PD-1/PD-L1, TGF-β), release of pro-inflammatory cytokines (e.g., IL-6, TNF-α), and dysregulation of nutritional metabolism (30, 31), thereby underpinning SIG’s stable predictive value across anatomical subsites.