PVR and breast cancer: NK, natural killer cell; ERK1/2, extracellular signal–regulated kinase 1/2; DNAM-1, DNAX Accessory Molecule 1; BRCA1, Breast Cancer 1, Early Onset; MHC, major histocompatibility complex; MK, megakaryocyte; HSC, haematopoietic stem cell; CXCR4, C-X-C Motif Chemokine Receptor 4; MICB, MHC Class I Polypeptide-Related Sequence B; PVR, Poliovirus Receptor; ANXA1, Annexin A1; RHAMM, Receptor For Hyaluronan-Mediated Motility; VEGFR1, Vascular Endothelial Growth Factor Receptor 1.