SPHK1 and ovarian cancer: In ovarian cancer, miR-124 is downregulated and has been identified to inhibit cancer progression by multiple mechanisms, including the regulation of cell migration and invasion through Sphingosine kinase 1 (SphK1) [107,108,109] and cell proliferation, cell death, and apoptosis by targeting programmed cell death 6 (PDCD6), a pro-apoptotic protein [110].