SPHK1 and mesothelioma: To further support the role of SphK1 in regulating mesothelioma cell proliferation by chromatin modification of targeted gene promoters, we examined the effect of SphK inhibitor on histone acetylation of Transcriptional Start Site (TSS; minimal promoter) regions of cell cycle related genes using chromatin immunoprecipitation (ChIP) with acetyl lysine antibody.