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A Paracrine Dietary Lipid Axis Constrains Antitumor Immunity in Liver Cancer

science

Overnutrition-related liver dysfunction and cancer are increasingly prevalent and highly resistant to immunotherapy. While metabolic dysregulation is a hallmark of hepatocellular carcinoma (HCC), how nutrient overload impairs antitumor immunity remains unclear. Here, we show that short-term Western diet (WD) exposure drives near-complete loss of CD8⁺ T cell infiltration and antitumor function in HCC. We identify dietary linoleic acid (LA), the most abundant ω-6 fatty acid, as the dominant immunosuppressive driver. Cancer cell-restricted FADS2-mediated desaturation of LA to longer-chain ω-6 PUFAs drives their accumulation in the tumor interstitial fluid, suppressing infiltrating CD8⁺ T cells via lipid peroxidation. FADS2 inhibition restores CD8⁺ T cell function and sensitizes WD-driven HCC to PD-1-based immunotherapy.

BioRxiv     Jul 02, 2026