The expression of T cell inhibitory ligands, including programmed death ligand-1 (PD-L1), PD-L2, carcinoembryonic antigen-related adhesion molecule-1 (CEACAM-1), lymph node sinusoidal endothelial cell C-type lectin (LSECtin), and major histocompatibility complex (MHC) class II, on cancer cells also affects the anti-tumor activity of activated CD8 positive T cells such as CTLs. This evidence concerns the gene CLEC4G and neoplasm.