PROM1 and neoplasm: CD133 + cells, characterized by high telomerase activities (a sign of stem cell activity) (Ludwig and Kornblum, 2017), have been used as a molecular biomarker for GSC (Cheng et al., 2009; Brown et al., 2017; Lu et al., 2018); the proportion of CD133 + cells is an independent risk factor for tumor growth and time to malignant progression (Zeppernick et al., 2008).