CXCR4 and glioblastoma: Several studies have also shown that antiangiogenic treatment with bevacizumab and B20, both VEGF inhibitors, as well as with VEGFR inhibitors leads to an elevation of CXCL12 and CXCR4 in vitro and in vivo in a GBM rat model as well as in a PDX mouse model [64,147].