In these studies, we also performed comprehensive gene expression analysis in the mouse liver with a microarray technique, which revealed that the expression of sphingosine kinase 1 (SPHK1) was significantly upregulated in the PDGFC-Tg mice and Ath-HF diet mice compared with control mice and that this increase was suppressed by peretinoin. Here, SPHK1 is linked to hydrops fetalis.