GDF15: A Hijacked Metabo-Hormone Orchestrating Cachexia and Immunosuppression in Cancer.

Cancer is responsible for systemic burdens, most notably cachexia and immunosuppression, that extend far beyond local tumor growth and collectively dictate poor outcomes. While often studied separately, these debilitating syndromes are deeply interconnected. On the basis of emerging evidence of growth differentiation factor 15 (GDF15)'s dual actions in immunity and metabolism, we propose that the stress-responsive hormone GDF15 is hijacked by tumors and repurposed as a central metaboceptive hub that integrates diverse oncogenic stress signals to launch a coordinated, dual pathological cascade. Systemically, it disrupts brain-body communication via glial cell line-derived neurotrophic factor family receptor alpha-like (GFRAL) activation in the brainstem, driving anorexia, metabolic rewiring, and progressive wasting of skeletal muscle and adipose tissue that define cachexia. GDF15 acts as a potent immunosuppressor within the local tumor microenvironment, impairing T cell cytotoxicity and increasing the abundance of regulatory T cells. Crucially, these effects are not parallel but interlinked, forming a self-reinforcing detrimental cycle that accelerates host deterioration and therapeutic failure. This positions the GDF15-GFRAL axis as a unique dual-benefit therapeutic target with the potential to simultaneously ameliorate cachexia, improve patient function and quality of life, and revitalize anti-tumor immunity. Reframing cancer through the lens of a hijacked metabolic sensing system provides an integrated perspective that transforms this formidable challenge of concurrent host wasting and immune evasion into a druggable opportunity, charting a course for novel host-directed therapies that restore systemic homeostasis.