CXCL8 and neoplasm: It is known that several soluble molecules are upregulated by MSCs in response to hypoxia, including cell cycle-regulating proteins such as VEGF and IGF-II [23, 28] and hypoxia-inducible factors (HIFs) with roles in the promotion of macrophage recruitment, primary tumor growth [32], and metastasis of breast cancer [32, 36] and induction of proangiogenic and chemotactic secretion factors such as MCP-1, IL-8, and RANTES [25].