Since downregulation of sphingosine kinase 2 should prevent the phosphorylation of FTY-720 and thereby also prevent inhibition of sphingosine 1-phosphate receptors by FTY-720, these data strongly suggest that FTY-720 does not act via inhibition of sphingosine 1-phosphate receptors expressed in the cancer cells. The gene discussed is SPHK2; the disease is cancer.