Genetics is not the only factor when it comes to cancer. Very topical today is the mutation of the BRCA1 and BRCA2 genes which can be inherited and give you a very high probability of getting breast cancer. But high probability means something in the region of 80% which means that 2 out of 10 people carrying the mutated gene, for some reason do not get sick. I read that genetics only accounts for 10-20% of the overall probability of getting cancer, but environmental factors and diet are also extremely important factors. One cannot win, but we can do our best to minimise our chances!