Linoleic acid metabolic reprogramming is linked to immunometabolic remodeling and post-transplant recurrence risk in hepatocellular carcinoma

Background Lipids serve as both metabolic substrates and signaling mediators that critically regulate immune cell fate, function, tolerance, and intercellular communication. In hepatocellular carcinoma (HCC), it remains unclear how intratumoral linoleic acid (LA) allocation between desaturation and oxidative catabolism influences immunometabolic remodeling and post-transplant recurrence. Methods Multi-omics profiling was conducted in a liver transplant-associated HCC cohort using paired tumor/non-tumor tissues and serum samples. The intratumoral lipid milieu (C4–C24 fatty acids) was quantified by targeted gas chromatography, whereas lipid–immune programs were resolved by single-nucleus RNA sequencing (snRNA-seq) integrated with targeted transcriptomic profiling. Key immune phenotypes and candidate genes were validated by serum inflammatory mediator profiling, flow cytometric lymphocyte immunophenotyping, spatially resolved tissue assays, and qRT–PCR. LA perturbation experiments provided functional support in vitro . Result Fatty acid profiling revealed that non-recurrent tumors were characterized by a higher intratumoral LA/AA ratio and a lower estimated Δ6-desaturation index than recurrent tumors, whereas recurrent tumors exhibited a higher estimated Δ6-desaturation index than their matched distant non-tumor liver tissues. snRNA-seq identified fatty acid catabolism as the most prominently downregulated metabolic pathway in recurrent tumors; malignant-cell analysis further highlighted EHHADH and ACSL3 as key genes involved in recurrence-associated lipid metabolic remodeling. In vitro , exogenous LA-BSA increased ROS accumulation and reduced SPP1 and NECTIN2 expression in HCC cells. Cell–cell communication analysis showed enhanced tumor–Treg signaling in recurrence, with VISTA- and CD80-related networks shifting from Kupffer cells toward SPP1 + macrophages and Tregs. Peripheral and tissue immunophenotyping showed reduced CD8 + T cells and higher IL-10 in recurrent tumors. Conclusion Multi-omics analyses indicate that, in primary pre-transplant HCC, post-transplant recurrence is associated with an imbalance between a higher estimated Δ6-desaturation index and attenuated oxidative catabolism-related features of linoleic acid, accompanied by Treg-associated immunosuppressive remodeling. These findings provide a biologically informed framework for post-transplant recurrence risk stratification and further translational investigation.