S1PR1 and ovarian cancer: Specially, our study provided the following new findings: (1) SphK1, but not SphK2, expression level was closely correlated with microvascular density (MVD) of ovarian cancer tissue; (2) The angiogenic potential and angiogenic factor secretion of ovarian cancer cells could be attenuated by SphK1, but not SphK2, blockage and were restored by the addition of S1P; (3) S1P induced the angiogenic factor expression via S1PR1 and S1PR3 in ovarian cancer cells; (4) Blockage of SphK or S1PR1/3 could effectively inhibit ovarian cancer angiogenesis.