CXCR4 and pancreatic neoplasm: Cancer therapy using an anti-VEGF Ab upregulated CXCR4 in rectal cancer cells [34], and upregulation of CXCR4 and increased invasiveness mediated by reactive oxygen species, NF-κB, and HIF-1α was observed in pancreatic cancer cells treated by the chemotherapeutic agent gemcitabine [35].