One other study explored the sphingosine kinase 1 (SphK1)/sphingosine-1-phosphate (S1P)/S1P receptor 2 (S1PR2) (SPHK1/S1P/S1PR2)-signaling pathway in GH-secreting pituitary tumors and assessed the effectiveness of the S1PR2 inhibitor JTE-013 [61], which showed abnormal SPHK1/S1P signaling in human GH-secreting pituitary tumors. This evidence concerns the gene SPHK1 and pituitary tumor.