CXCR4 and neoplasm: Strikingly, inhibition of MRE11 nuclease activity had no effect on tumor proliferation and metastasis, with our data indicating that MRE11 may separately mediate these effects via a nuclease independent pathway involving RUNX2—a transcription factor which promotes CXCR4 expression, AKT activation, and subsequent inhibition of FOXA2/E-Cadherin activity.