As previously reported,32 mRNA level and SphK1 activity were markedly decreased (60–90% range) in all cancer cell lines (prostate PC-3, lung A549, glioblastoma U87, ccRCC CAKI-1 and A498) treated with siSphK1 compared with scrambled siRNA (siScr) (Figure 1a). Here, SPHK1 is linked to glioblastoma.