Lead: A phase I study evaluating adoptive natural killer (NK) cell infusions for recurrent hepatocellular carcinoma (HCC) after liver transplantation reported tolerability and preliminary anti-tumor activity. Investigators including Yang and colleagues tested donor-derived NK cell products in a small cohort of post-transplant patients who have limited treatment options. The trial focused on safety endpoints and immune correlates; researchers observed acceptable toxicity and early evidence of disease stabilization or partial responses in select patients. The report underlines the feasibility of cell-based immunotherapy in a complex immunosuppressed, post-transplant setting. Transplant centers and oncology groups cited the data as justification for dose expansion and biomarker-driven cohorts to understand persistence, graft-versus-host risks, and compatibility of NK therapies with immunosuppression regimens.