Advances in the molecular subtyping of gastric cancer.

Despite decades of significant progress in gastric cancer research, the prognosis remains poor because of the disease's high aggressiveness. Historically, gastric cancers were classified based on histopathology and anatomical site-criteria that inadequately support precision therapy. Advances in molecular technologies have produced multiple molecular classification schemes, among which the Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG) classifications are the most mature and widely applied. In this review, we systematically summarize molecular subtypes of gastric cancer and explore their underlying molecular mechanisms, therapeutic implications, and prognostic associations. The evidence indicates that molecular subtyping is a key basis for improving precision therapy and enhancing patient outcomes: TCGA and ACRG provide clear clinical guidance, while emerging classifications offer new directions for individualized treatment and support the clinical translation of precision oncology in gastric cancer.