CD226 and hepatocellular carcinoma: To assess whether the CD155/DNAM-1 axis was altered in HCC patients, we examined NK cell function by reverse antibody-dependent cellular cytotoxicity (rADCC) assay, in which unstimulated or IL-15-stimulated PBMCs, TIL, and matched LIL cells, were incubated with FcγR+ P815 murine target cells in the presence of an anti-DNAM-1 specific mAb.