CXCR4 and neoplasm: Complicated mechanisms contributed to rapid tumor progression and inferior clinical outcomes in GBMs invading SVZ, including, but not limited to, tumor formation and propagation owing to aberrant Notch pathway activation and promoted invasion by pleiotrophin, which activated RhoA/ROCK signaling and weakened radiosensitivity induced by CXCL12 (stromal cell-derived factor-1), which, in turn, mediated acquired mesenchymal traits by the CXCL12/CXCR4 signaling system (35–37).