Epithelial–mesenchymal transition (EMT) is known to play an important role in cancer
progression, metastasis and drug resistance. Although there are controversies surrounding the causal
relationship between EMT and cancer metastasis, the role of EMT in cancer drug resistance has
been increasingly recognized. Numerous EMT-related signaling pathways are involved in drug
resistance in cancer cells. Cells undergoing EMT show a feature similar to cancer stem cells (CSCs),
such as an increase in drug efflux pumps and anti-apoptotic effects. Therefore, targeting EMT has
been considered a novel opportunity to overcome cancer drug resistance. This review describes
the mechanism by which EMT contributes to drug resistance in cancer cells and summarizes new
advances in research in EMT-associated drug resistance.