Moreover, sphingosine-1-phosphate (S1P) stimulates CXCL12-promoted MM cell adhesion to α4β1 ligands (141), and targeting S1P with FTY720 reduces CXCR4 cell-surface levels and inhibits in vitro and in vivo MM cell migration toward CXCL12 (142). Here, CXCR4 is linked to Miyoshi myopathy.