CXCR4 and cancer: In other studies, CXCL12–CXCR4 signalling was shown to stimulate pancreatic cancer cell proliferation and protection of cancer cells from serum deprivation-induced apoptosis (Koshiba et al, 2000; Marchesi et al, 2004; Saur et al, 2005; Marlow et al, 2008).