RPS6 and glioblastoma: Based on the results showing the overexpression of pRPS6 in highly malignant patients and predominantly expressed in GSC niches (Figure 4 and Figure 5), we additionally investigated the expression of ribosomal protein S6 kinase (RPS6K), an upstream kinase phosphorylating RPS6, by IVY GAP (glioblastoma atlas project) database (http://glioblastoma.alleninstitute.org/, accessed on 1 November 2021).