QKI and glioblastoma: Located in the 6q25-27 chromosomal region, PRKN is commonly lost/deleted in GBM similar as QKI, and PARKIN protein expression was shown to be downregulated during glioma progression (Cesari et al., 2003; Freije et al., 2004; Veeriah et al., 2010; Xu et al., 2014; Lin et al., 2015; de Castro et al., 2021).