The epithelial-to-mesenchymal transition (EMT) is a crucial process in tumour 
progression providing tumour cells with the ability to escape from the primary 
tumour, to migrate to distant regions and to invade tissues. EMT requires a loss 
of cell-cell adhesion and apical-basal polarity, as well as the acquisition of a 
fibroblastoid motile phenotype. Several transcription factors have emerged in 
recent years that induce EMT, with important implications for tumour 
progression. However, their effects on cell polarity remain unclear. Here, we 
have re-examined the data available related to the effect of EMT related 
transcription factors on epithelial cell plasticity, focusing on their impact on 
cell polarity. Transcriptional and post-transcriptional regulatory mechanisms 
mediated by several inducers of EMT, in particular the ZEB and Snail factors, 
downregulate the expression and/or functional organization of core polarity 
complexes. We also summarize data on the expression of cell polarity genes in 
human tumours and analyse genetic interactions that highlight the existence of 
complex regulatory networks converging on the regulation of cell polarity by EMT 
inducers in human breast carcinomas. These recent observations provide new 
insights into the relationship between alterations in cell polarity components 
and EMT in cancer, opening new avenues for their potential use as therapeutic 
targets to prevent tumour progression.