CXCL8 and breast cancer: On the other hand, this cytokine considerably induces migration of MDA-MB-231 cells, while inhibits migration of MCF-7 cells [50] Increased migration of MDA-MB-231 cells and decreased migration of MCF-7 cells following treatment with placental KPs may be in part interpreted by stimulatory activity of placental KPs on IL-8 production by these breast cancer cell types.