As a cancer researcher, I'm unable to resist de-lurking for a bit of Friday afternoon pedantry. While you're generally correct that DNA damage is required the radiation could have an indirect effect e.g. stressing the cell, resulting in oxidative damage to the DNA. That being said, I've never seen any reliable data to support a radiation->cancer link. (Which doesn't mean that I'm not happy to see that the N900 has lower SAR than the N82 I'll be trading in. )