SELP and cancer: P-selectin-bound metastatic cancer stem cells were found to be resistant to shear stress, which highlights the strength of sLex binding to P-selectins in a circulating fluid environment.128 Meanwhile, L-selectins have been implicated in monocyte recruitment, promoting lung metastasis through enhanced extravasation.93,129 A study undertaken by Mondal et al.130 has demonstrated that ST3Gal IV is the primary sialyltransferase that synthesises sLex and other selectin ligands on human myeloid leukocytes, facilitating tethering to the vascular endothelium (Fig. 4).130