TK1 and gastric cancer: The thymidine kinase enzymatic family, particularly thymidine kinase 1 (TK1, EC 2.7.1.21), serves as an enzymatic orchestrator of deoxyribonucleotide salvage pathways critical for genomic integrity maintenance, and its oncogenic overexpression acts in concert with <i>Helicobacter pylori</i>-mediated chronic inflammatory microenvironments, and potentiates the histopathological progression from premalignant metaplasia review delineates the utility of TK1 as a serological biomarker for early detection, tumor staging, therapeutic monitoring, and prognostic stratification in GC.