Yu et al. (65) found that Tumor necrosis factor-α (TNF-α)-activated MSCs promote breast cancer metastasis via production of CXCL1, CXCL2, and CXCL5 to recruit CD11b+Ly6G+ CXCR2+ neutrophils, and then neutrophils activate tumor cells to express higher levels of metastasis-related genes including CXCR4, CXCR7, MMP12, MMP13, IL-6, and TGFβ. The gene discussed is CXCL1; the disease is neoplasm.