SPHK1 and cancer: Regarding SkM atrophy, our group reported that SphK/S1P signaling and the ceramide kinase/ceramide-1-phosphate (C1P) axis are unpaired in in vivo cachectic mice as well as in an in vitro model of cancer cachexia, represented by dexamethasone (Dexa)-treated myotubes [19,31,42,78], suggesting a role for these bioactive lipids in preserving the SkM cell phenotype.