CXCR1 and neoplasm: Interestingly, REEP5 and REEP6 activate interleukin-8 (IL-8)/CXC chemokine receptor 1 (CXCR1, a G-protein coupled receptor) signaling to promote tumor cell proliferation/migration, angiogenesis, and macrophages/neutrophils recruitment in the tumor microenvironment in lung cancer [21].