OFF OR REALLY OFF
Cancer is the result of gene expression gone awry, with some genes silenced that shouldn’t be, and others turned on aberrantly. Now Stephen Baylin and colleagues at Johns Hopkins have identified similarities and differences in gene expression between embryonic cells and cancer cells.
BAYLIN: We know that many of our genes that get really, fully silenced in cancer cells, very stably silenced, they can’t be reactivated even if the cell wants to. Those same genes are also marked for silence in the embryonic cells, but there’s a fundamental difference. In the embryonic cells the gene is marked for low expression but it has to come on when needed, so it has a mark called polycomb proteins. The cancer cells have some polycomb proteins but they have an additional mark called DNA methylation that really seems to be an abnormal mark. :31
Understanding how this process is regulated points the way toward very targeted cancer interventions. At Johns Hopkins, I’m Elizabeth Tracey.