CXCR4 and neoplasm: Vascular endothelial growth factor (VEGF) is the most important and best characterized angiogenic factor and also the target of the anticancer drug bevacuzimab.12 The interaction of CXCR4 and SDF1 could advance tumor progression and metastases through the induction of VEGF-mediated angiogenesis.13 Furthermore, HIF1 is known to regulate the activation of VEGF directly (See Supplemental Fig. 1).14,15