[thedoc (OP)]

Shaya Kass asked the Naked Scientists:
   
I once heard on your show that heart cancer is very rare because heart cells don't reproduce that often and skin cancer is more common because skin cells are always reproducing.

Based on that, why is brain cancer so common? Do brain cells reproduce that often? I thought they cannot reproduce, hence, it is very difficult to regenerate brain cells after an injury.

What do you think?

[evan_au]

When people talk about brain cells, they normally focus on the neurons.

However, there is another group of cells (having several subgroups), called glial cells, which do not appear to receive so much attention. Some cancers arise in the glial cells (gliomas).

And cancers from any part of the body can spread (metastasize) into the brain.

See: https://en.wikipedia.org/wiki/Brain#Cellular_structure
https://en.wikipedia.org/wiki/Brain_tumor

[RD]

Primary brain tumours, i.e. ones which originate in the brain, rather than metastasize from elsewhere in the body, only occur in ~1 in 5000 people ...
http://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/brain-other-cns-and-intracranial-tumours/incidence#heading-Five

[MayoFlyFarmer]

1:5000 isn't all that rare.  Given the prognosis for most brain cancers, I'd like better odds than that!