i) PVR and Nectin-2 have been described as tumor antigens and are molecular targets of NK cells through the interaction with the DNAM-1/CD226 molecule [14], ii) PVR is overexpressed in tumors of hematopoietic, neuronal and epithelial origins [15-17], iii) Nectin-1 is overexpressed is squamous carcinomas [18], and iv) Afadin is ubiquitously expressed in epithelia, and its loss has been associated with poor outcome in breast carcinoma [19]. This evidence concerns the gene CD226 and breast carcinoma.