CXCR4 and permanent neonatal diabetes mellitus-pancreatic and cerebellar agenesis syndrome: Importantly, we have demonstrated that even when GEM-R PaCa cells were activated by GEM, the blockage of the CXCL12-CXCR4 signaling axis by CXCR4 antagonists had impacts on GEM-R PaCa cell proliferation, invasion and tumorigenicity both in vitro and in vivo.