CXCR4 and neoplasm: In pancreatic cancers, these events have been shown to be mediated by a specific subpopulation of CSCs characterized by CD133 expression, a stemness marker, and CXCR4 overexpression with respect to parenchymal tumor cells; they are localized at the invasive front of the mass, suggesting a role in tumor dissemination due to the expression of CXCR4 and the responsiveness to the specific ligand CXCL12 produced by other cells present in the microenvironment.