VTCN1 and neoplasm: Recently, five new B7 family ligands—B7 homologs 3 to 7 (B7-H3 to -H7)—were identified. Expression of the co-inhibitory molecule B7-H4 in cancer cells may be associated with tumor progression, due to its inhibition of T cell proliferation and cytokine production in the tumor microenvironment [15].