Problem:
First of all let me say that I'm not into Biology myself... but I have a question for those of you who are.
From what I've read, cancer is caused by 'faulty' DNA that behaves abnormally. Mutations can occur for various reasons, ranging from simple 'copying errors' to environmental factors.
I was just wondering whether current research has dealt with storing DNA of people or animals (e.g. rodents) and observing how it changed, especially for cases where it eventually resulted in cancer. Something along the lines of this, but I'd like to know what research has actually been done so far. Please justify it.