CXCL12 and exocrine pancreatic carcinoma: Pancreas carcinoma microenvironment contains the angiogenesis stimulating factors VEGF, PDGF, FGF1, FGF2, collagen-I, periostin, adrenomedullin, prokineticin-1, MMPs and uPA, the migration-stimulating factors PDGF, EGF and SDF-1, proliferation stimulating factors such as TGFß, FGF2, PDGF, EGF, CTGF, adrenomedullin [61], Gal-3, and SDF-1, invasion promoting factors such as MMPs, thrombospondin [62], uPA, and tPA, and factors responsible for drug resistance (NO•, IL-1ß) and inhibition of anoikis/apoptosis (collagens, fibronectin, laminin).