GDF15 in the tumor microenvironment: A central mediator of cancer immunometabolism and therapeutic resistance.

Growth differentiation factor 15 (GDF15), a divergent member of the transforming growth factor-β (TGFβ) superfamily, has emerged as a pivotal cytokine linking cancer metabolism, immune suppression, and systemic energy balance. Initially characterized as a stress-induced cytokine with roles in appetite regulation and cachexia, GDF15 was first identified in activated macrophages and is also secreted by tumor cells, stromal cells and stressed epithelial cells across multiple tissues. Functionally, GDF15 exerts pleiotropic effects on both immune and nonimmune cell populations, modulating T cells, dendritic cells, and macrophages in the tumor microenvironment (TME), and metabolic tissues such as liver, adipose and muscle, thereby promoting tumor progression, therapeutic resistance, and cancer-associated metabolic dysregulation. In several human cancers of such as colorectal, pancreatic, breast and brain, elevated GDF15 levels correlate with poor prognosis, immune evasion, and chemoresistance. Mechanistically, GDF15 modulates fatty acid metabolism, promotes epithelial-mesenchymal transition, and suppresses anti-tumor immunity by impairing dendritic cell maturation and excluding CD8+ T cell infiltration. Targeting GDF15 may reprogram immunometabolic suppression and enhance checkpoint blockade efficacy. This review synthesizes current knowledge on GDF15's multifaceted roles in tumor biology, emphasizing its function as a central node of cancer immunometabolism. We highlight advances in spatial multi-omics, integrating transcriptomics and immune imaging, that reveal GDF15 spatially restricted immunosuppression in the tumor microenvironment.