ERN1 and breast cancer: Interestingly, the inhibition of IRE1α activity by MKC8866 in breast cancer cells triggers decreased production of pro-tumorigenic factors such as Interleukin 6 (IL-6), Interleukin 8 (IL-8), chemokine (C-X-C motif) ligand 1 (CXCL1), transforming growth factor-β2 (TGFβ2), and granulocyte-macrophage-colony-stimulating factor (GM-CSF) as well as enhancing breast cancer cell response to chemotherapy [165].