PVR and melanoma: Human CD155 and CD112 are broadly distributed on epithelial and endothelial cells in many tissues [10, 11]; notably, they are overexpressed on various tumors, including colorectal [12, 13], gastric [12], and ovarian cancers [14]; neuroblastoma [15]; myeloid leukemias [16]; multiple myeloma [17]; and melanoma [18].