Abstract
Human glycyl-tRNA synthetase (GARS), encoded by the GARS1 gene, is a key protein within the aminoacyl-tRNA synthetases family, responsible for catalyzing the attachment of glycine to its corresponding tRNA during protein synthesis. While aminoacyl-tRNA synthetases are primarily known for their role in translation, emerging evidence indicates that they also have non-canonical functions in physiological and pathological processes, including metabolism, angiogenesis, immune responses, and inflammation. This review integrates glycyl-tRNA synthetase evolutionary origins, isoform biology, structure function relationships, immune roles, and cellular stress evidence across bladder, prostate, breast, colorectal, and hepatocellular tumors. Unlike prior papers about GARS, we (i) distinguish cytosolic vs mitochondrial GARS isoforms and their detection pitfalls; (ii) synthesize non-canonical mechanisms (neddylation interfaces, extracellular vesicles-mediated C-ter and N-ter peptides, CDH6-dependent signaling); and (iii) provide a comparative reliability map across cancers, identifying urinary bladder cancer as the most substantiated indication with convergent transcriptomic, proteomic, metabolic, and preliminary translational evidence. Current literature is dominated by correlative and in-vitro studies, and prospective clinical validation is scarce. GARS is a promising but incompletely defined oncologic and immunobiologic node; targeted, standardized, and clinically anchored studies are now feasible and necessary.