CXCR4 and glioblastoma: Interestingly, the PN subgroup with lower levels of PATZ1 showed increased levels of the G-protein coupled receptor CXCR4, a well-known inducer of the mesenchymal phenotype in GBM [29,30], which has been shown to be downregulated by PATZ1 overexpression in GBM cells [28].