Cancer Stem Cells (CSC) comprise a concept proposed in the 1990s in hematopoietic cancers.
These cells were considered, by similitude to normal stem cells, to constitute a small pool of
self-renewing cells able to maintain a tumor. Due to their quiescence, CSC would be able to avoid
chemotherapeutics targeting fast proliferation rates, or radiotherapy, thus being responsible for tumour
relapse. Since CSCs have also been implicated in invasion and metastasis and epithelial to mesenchymal transition (EMT)
was proposed as a determinant of malignancy in epithelial cancers, the relationship between EMT and CSC is an important
issue, which has been increasingly addressed in recent patents on CSC biology. A thorough search for a more accurate
identification of these cells, as well as more effective drug search yielded a number of interesting research patents
during the last 5 years, several of which are to be detailed in the present review.