CXCL8 and neoplasm: It is believed, that following accumulation at the sites of tumor formation and growth, MSCs differentiate into pericytes or tumor-associated fibroblasts (TAF) thereby forming a growth supporting microenvironment and secreting such trophic factors as vascular endothelial growth factor (VEGF), interleukin 8 (IL-8), transforming growth factor β (TGF-β), epidermal growth factor (EGF), and platelet-derived growth factor (PDGF).