CXCR4 and neoplasm: MSCs were selected over other membrane typologies since it has been reported on their intrinsic homing ability toward injured and inflamed sites such as tumors, mainly thanks to the expression on their surface of multiple receptors for the recognition of specific molecules (e.g., C-X-C chemokine receptor type 4 (CXCR4), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR)), released in the tumor microenvironment [32]).