SLC22A5 and glioblastoma: OCTN2 expression level has been recently shown to be higher in more aggressive glioblastomas, hence representing a negative prognostic marker in these patients, likely because of a higher accumulation of L-carnitine, which is an important co-factor in energy metabolism and a potent antioxidant (Gulcin, 2006; Fink et al., 2019).