SPHK1 and congenital diaphragmatic hernia: Zimmer et al studied nitrofen-induced CDH rats, and performed QRT-PCR, western blotting and confocal-immunofluorescence microscopy to reveal pulmonary gene and protein expression levels of sphingosine kinase 1, sphingosine-1-phosphate 1, 2, 3 and Ras-related C3 botulinum toxin substrate 1 (Rac1) [22].