For other more poorly understood TNF ligand-receptor signaling pathways such as the immune- costimulators which are believed to be promising immuno-oncology therapeutic targets27,28 – including 4-1BBL/4-1BB, OX-40L/OX-40, GITRL/GITR, CD30L/CD30, LIGHT/HVEM and CD70/CD27 – AP-tagged TNFSF ligands could similarly be used to help elucidate their differential expression, signaling and functional roles in immune-surveillance of cancer. The gene discussed is CD70; the disease is cancer.