Of note, neurospheres derived from different continuous GBM cell lines had high levels of RYK mRNA (Figure 1D) and/or protein (Figure 1F) beside other well-established GSC markers, including NANOG, SOX2, OCT3/4 (Figure 1E and 1F), NESTIN, CD133, and EZH2 (Supplementary Figure 1B and 1C). Here, NANOG is linked to glioblastoma.