Question: How does cancer travel to the brain?

Robert Insall answered on 21 Nov 2012:

Hallo again gothgirl. I totally agree about practicals (on your profile page). But you can do them at home, too. Me and my kids are planning to build a little van der Graaf generator over Christmas.

Cancer travels to the brain through the bloodstream. Some cancer cells break away from the tumour and move into the blood (why? Dunno yet – that’s what I work on). Once they’re in the bloodstream they can spread to the liver, lungs, bone or brain.

Only some cancers go to the brain, because they have to squeeze through something called the blood-brain barrier which exists to keep your brain safe from poisons. Why do they squeeze through the blood brain barrier? I don’t know yet.

(do you see the theme here? Scientists are not interested in things we understand. We’re interested in things we don’t understand, if we think we could understand them after a few years’ study)