SPHK1 and glioma: Based on the gene expression analysis result of 20 human glioma samples and 5 normal human brain samples, we found that the FA desaturase 2 (FADS2), several phospholipase 2 (PLA2) associated with membrane lipid metabolism, two lysophospholipases (LYPLAs), PI 4-kinase type 2 beta, two AKT serine/threonine kinases (AKTs), N-acylsphingosine amidohydrolase 1 (i.e., the acid ceramidase [ACDase]), SM phosphodiesterase 2 (i.e., the neutral sphingomyelinase), and sphingosine kinase 1 were upregulated in human glioma (see supplemental Table S2 for details).