ACKR3 and glioma: The increase of CXCR7 expression in microvascular endothelial cells during hypoxia (Schutyser et al., 2007; Monnier et al., 2012) favors CXCL12-induced glioma cell migration (Esencay et al., 2013) facilitating the binding of CXCL12 to endothelial cells (Burns et al., 2006; Liu et al., 2010; Dai et al., 2011) and the activation of CXCL12-mediated cell crossing through endothelium (Mazzinghi et al., 2008; Zabel et al., 2009; Dai et al., 2011).