CXCL8 and neoplasm: Since the treatment of our PN GSCs did not induce an upregulation of the important MES transcriptional regulators STAT3, C/EBPβ and TAZ [42, 43], we hypothesize that IL-8 upregulation is not necessarily instructive for the MES subtype of these GSCs, but moreover a side-effect of the subclass transcriptional pattern that is active in the tumor cells.