no one knows why anyone gets any cancer, to me they are all scientific myths. It could be your blood group for all we know. I smoked so straight away, that was the reason I had bladder cancer, I have 7 siblings, they all smoke but they have never had cancer, my father passed with bowel cancer but never smoked, my grandmother passed of cancer but never smoked. We all carry the cancer gene. My husband and I are RH pos blood group, my children are neg blood group as both parents need to carry the hidden neg gene. I can't answer if its in the food, water etc but it exists and we are either lucky or not.