BST2 and cancer: Many cancer types express de novo, or overexpress, IR ligands which often represent a strong predictor of poor outcome and metastasis, as observed for BST2 (148), PCNA (208), HLA-G (168), galectin-9 (186), CEACAM-1 (186, 187) and modifications of cell surface carbohydrates capable to trigger CLRs (128–130).