Like snakes, tumour cells shed their skin. Cancer is not a static disease but during its development the disease accumulates changes to evade natural defences adapting to new environmental circumstances, protecting against chemotherapy and radiotherapy and invading neighbouring organs, eventually causing metastasis.
The study was conducted mainly in breast and colon tumours. Besides serving to better understand the disease, the results are important because they predict that external intervention is possible in the process. In this sense, drug treatments can reverse the process and move from a highly evolved tumour form to a more primitive form, which would be associated with a slower progression of the disease.

Article reference

V Davalos*, C Moutinho*, A Villanueva*, R Boque*, P Silva, F Carneiro, and M Esteller*. Dynamic epigenetic regulation of the micro RNA-200 family mediates epithelial and mesenchymal transitions in human tumorigenesis. 2011 Aug 29. doi: 10.1038/onc.2011.383. [Epub ahead of print]