CD209 and neoplasm: Potential LAG3 ligands include: 1) Liver sinusoidal endothelial cell lectin (LSECtin), a member of the DC-SIGN family, which is expressed in the liver and on melanoma cells, where it functions to inhibit anti-tumor CD8+ T cell [51] and NK responses; 2) galectin-3, which is expressed by stromal cells [52,53] and CD8+ T cells in mice [54], which can bind LAG3 under conditions of heavy glycosylation [44]; 3) α-synuclein in neurons [55]; and the recently demonstrated fibrinogen-like protein 1, released in the liver (at low levels) and by tumor cells [34] ( Figure 1; Figure 2).