Cell de-differentiation is an important step towards tumor generation. A group in Leipzig shows upregulation of hundreds of developmental genes, and link that to loss of chromatin poising. They show that this effect can be seen in virtually all cancers. This leads them to the hypothesis that loss of poising is what causes cell dedifferentiation.
More than 5k samples were analyzed in this study and the effect can be seen in 90% of the samples.
Stephan H Bernhart, Helene Kretzmer, Frank Jühling, Peter F Stadler, Steve Hoffmann: 'Disturbance of poised chromatin coincides with increased expression of developmental genes in cancer'., bioRxiv, 2015 - doi: http://dx.doi.org/10.1101/017251