Unlocking the potential: current landscape and future directions of immunotherapy in gastric cancer

Gastric cancer (GC) ranks as the third leading cause of cancer-related mortality worldwide, and its management remains formidable. Immunotherapy has been highly praised for its remarkable efficacy and acceptable toxicity, and its development has outpaced that of traditional therapies. However, molecular heterogeneity and the immunosuppressive tumor immune microenvironment (TIME) have hindered the treatment response of a considerable number of patients. This review synthesizes the latest therapeutic advances, spanning immune-checkpoint inhibitors (ICIs), adoptive cell therapy (ACT), monoclonal antibodies and antibody drug conjugates (ADCs), cancer vaccines, tumor-infiltrating lymphocyte (TIL) therapy, and CAR-T cells therapy. Emerging strategies such as RNA interference nano-delivery systems, immune adjuvants, and microbiota modulation are constantly evolving to transform "cold" tumors into "hot" tumors. Persistent challenges include primary resistance, immune-related adverse events (irAEs) and antigenic heterogeneity, underscoring the imperative for refined patient stratification. Classical biomarkers such as PD-L1 expression, tumor mutational burden (TMB), mismatch-repair status, Epstein-Barr virus (EBV) positivity and circulating tumor DNA (ctDNA) all demonstrate predictive value but remain constrained by spatial heterogeneity and temporal dynamics. Consequently, we highlight emerging biomarkers that integrate metabolic, epigenetic and cell-death signatures, providing a roadmap for precision immunotherapy and continuous optimization of GC treatment algorithms.