TNFSF18 and neoplasm: The TNFR superfamily proteins are expressed by antigen-presenting cells (APC) or tumor cells, including TNFSF4 (OX40L), TNFRSF5 (CD40), TNFSF7 (CD70), TNFSF9 (CD137L), TNFRSF14 (HVEM), and TNFSF18 (GITRL) [10].