NUCLEOLIN and central nervous system cancer: AS1411 downregulates the astrocytes’ exosome-miRNA-27a-mediated cross-activation of glioblastoma by the following sequential events: binding to NCL, translocation into nucleus and binding to NF-κB pathway transcription factor P65, downregulation of miRNA-27a and upregulation of the target gene of miRNA-27a in gliomas (INPP4B), and finally the inhibition of the PI3K/AKT pathway and of glioma proliferation.