ZEB1 and breast cancer: We have already shown that EPB41L5 promotes the drug resistance of breast cancer cells, such as MDA-MB-231 and MDA-MB-435s, both of which express every component of the ARF6-based pathway at high levels.28 Involvement of ZEB1 in drug resistance has also been documented in pancreatic cancers.38, 39, 40 We then sought to understand whether other components of the ARF6-based mesenchymal pathway are also involved in promoting the drug resistance.