CXCR4 and central nervous system cancer: On the basis of these previous data, pointing to links between PC-PLC enzyme activation and growth factor receptors’ status and in light of our previous study on CXCR4 in U87MG glioma cells [11], in the present work we investigated the possible cross-talk between CXCR4 and PC-PLC in U87MG cells using the competitive PC-PLC inhibitor D609 [21] and compared the effects of this agent with those exerted by a conventional CXCR4 antagonist (Plerixafor).