TIGIT and neoplasm: Consistently, the immune checkpoint ligand nectin cell adhesion molecule 2 (NECTIN2) for T cell immunoreceptor with Ig and ITIM domains (TIGIT) was highly expressed in the infiltrating cells of the tumor microenvironment, while the expression of CD274 (programmed death-ligand 1 [PD-L1]) and programmed cell death 1 ligand 2 (PDCD1LG2; PD-L2), which correspond to programmed cell death 1 (PD-1), was not prominent (Fig. 2J).