Interestingly, the binding of P-selectin to a tumor cell surface depends on the expression of the CHST11 gene encoding chondroitin 4-O-sulfotransferae-1 (C4ST-1), and CSPG4 (also known as melanoma-associated CSPG) serves as a P-selectin ligand through its CS side chains and participates in the binding of P-selectin to highly metastatic breast cancer cells [9]. The gene discussed is SELP; the disease is breast cancer.