To investigate the expression of AGR2 and GRP78 in glioblastoma CSCs detected in tissues and corresponding cell lines, AGR2 was co-stained with Nestin, SSEA4 or Vimentin, and GRP78 was co-stained with SOX2, Frizzled 9 and TUBB3 (Fig. 2). Here, FZD9 is linked to glioblastoma.