CXCR2 and neoplasm: For example, IL-8 produced by a range of immunological cells (such as neutrophils, macrophages, mast cells, etc.)and TCSCs, which specifically bind to CXCR1 and CXCR2, not only promote TCSCs’ self-renewal, sphere formation, and tumor-initiating ability through autocrine circuits but also maintains TCSCs stemness traits through paracrine Akt-Slug-dependent pathways and tumor initiation capacity (60–63).