A newly discovered LAG-3 ligand produced by liver and cancer cells—fibrinogen-like protein 1 (FGL1)—has been identified to mediate antigen-specific T-cell suppression.21 Increased LAG-3 expression on CD4+ and CD8+ T cells is associated with liver metastasis in mismatch-repair-proficient colorectal cancer. The gene discussed is FGL1; the disease is colorectal cancer.