PVR and cancer: As indicated above, some members of this Nectins and Necls family (Nectin-2 and Necl-5) have attracted great interest for their potential use as cancer biomarkers, as they are overexpressed on a variety of tumor cells from different origins, and as potential targets in cancer immunotherapy as they can be recognized by activating and inhibitory paired-receptors expressed on NK cells [23,32,33,34].