SPHK1 and cancer: The most commonly used pharmacological inhibitors are sphingosine analogues (especially N,N-dimethylsphingosine, DMS, and DL-threo-dihydrosphingosine, DHS); both are potent competitive inhibitors of Sphk1 [24], leading to cancer cell growth inhibition in vitro and in nude mice, and enhanced apoptosis in the cancer cells of colorectal, breast, prostate, gastric, and lung.