TNFRSF11B and bone neoplasm: Moreover, in the treatment of bone metastases, Segaliny and co-authors demonstrated that MSCs designed to overexpress P-selectin glycoprotein ligand-1 (PSGL-1)/Sialyl-Lewis X (SLEX) and modified versions of cytosine deaminase (CD) and osteoprotegerin (OPG), had better homing toward metastatic bone tumor cells, possibly due to interactions between the PSGL-1/SLEX expressed by MSCs and the P-selectin expressed by endothelial cells at the vascular level of the tumor.