I won't claim to be a cancer expert, but I am doing a chemistry degree, and have a sister who has a masters degree in cancer research, so feel I'm generally pretty well informed. The way I see it, news papers, journals, tv....they all love a good cancer scare story. There are just as many research articles proving something causes cancer as there are articles that will say it doesn't. Personally, I think the benefits of taking insulin way WAY outweigh any risks. You can find news stories claiming virtually anything causes cancer. Don't smoke, stick to a healthy weight, don't spend your life in the sun without sun cream on...and I'd say you're pretty well covered.