Friday, February 16, 2007

Sharks DO get cancer

I just gave a journal club about a trio of papers out this week in Nature Genetics. They support an interesting theory that stem cell and cancer cell self renewal is controlled by Polycomb repressor complexes (PcG). They maintain tumour supressors in a repressed but still free to be activated and thus "bivalant" chromatin environment in stem cells. However with time and because of epigenetic drift these supressor complexes tend to recruit DNA methylation and the tumour supressor become irreversibly repressed, thus with a "locked-in" stem-ness. This could be regarded as the "first" hit of the two hit transformation driving a stem cell into a cancer cell. Interresting paper, although you never know these days whether to trust stem cell papers, I guess the gold rush mentality attracts fraud.
Following JC I discussed the significance of said papers with the Ken-meister, and proposed that maybe sharks do not keep stem cells around and that is why they don't develop cancer. To which Ken replied yes they do! So I must correct myself from the podcast, although the incidence rate is low compared to other fish there has been cases of tumours including Chondromas! Oh the irony, I guess shark cartilage is not going to save you, however wrestling shark while intoxicated on vodka is still ok...


Anonymous said...

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