EMT in carcinoma progression and dissemination: facts, unanswered questions, and clinical considerations.

Over the past decade, much effort has been made to understand how cancers metastasize. In deciphering the metastatic process, a vast amount of work has focused on the role of the epithelial to mesenchymal transition (EMT), which, in experimental models, confers tumor cells with invasive and metastatic abilities, resistance to therapies, as well as cancer stem cell phenotype-properties that have a major impact on cancer prognosis. Searching "EMT and cancer" in PubMed retrieves thousands of original research articles, yet, we haven't answered the most basic question in the field: has EMT any relevance in human tumors?