To further elucidate the downstream pathway mediating the influence of SIP on CML progression, we examined the effects of specific inhibitors of five S1P receptors (S1PR1-5) on CML cell growth and found that the S1PR3 inhibition group showed the most significant decrease in cell growth. This evidence concerns the gene S1PR3 and chronic myelogenous leukemia, BCR-ABL1 positive.