CXCL8 and breast cancer: M2-related genes such as IL-8, IL-10 and TGF-β were upregulated in the THP-1 cells cultured in the breast cancer cell CM compared to the controls (Figure 2A, 2B and 2C), whereas the expressions of M2-related genes were attenuated (Figure 2A, 2B and 2C) and the expressions of M1-related genes IL-12 and TNF-α were enhanced (Figure 2D and 2E) in the THP-1 cells cultured in the CM from breast cancer cells pretreated with metformin.