SPHK1 and hepatocellular carcinoma: Additionally, diethylnitrosamine (DEN)-induced hepatoma was significantly fewer and less frequent in SPHK1 knockout mice compared to wild-type mice Collectively, our results suggest that one of the mechanisms by which peretinoin prevents hepatocarcinogenesis would be suppression of SPHK1 expression and that the SPHK–S1P axis could be a promising target for HCC therapy.