Moreover, CXCL6 production by endothelial cells within gastrointestinal tumors was shown to contribute to tumor development and neovascularization [23] and constitutive CXCL6 secretion was recently demonstrated in a panel of small cell lung cancer (SCLC) cell lines and in clinical SCLC specimens [37]. This evidence concerns the gene CXCL6 and digestive system neoplasm.