DEAR DOCTOR K: I thought cancer was the result of risky behaviors like smoking and spending too much time in the sun. But then I read an article about cancer and bad luck. So which is it -- behaviors or luck?
DEAR READER: I know the article you are referring to, and I wasn't very happy with the way it was presented by the media. Let me start with the bottom line: Cancer is caused by (1) our genes, and by (2) our lifestyle (risky behaviors) and environment. It's not just one or the other. Sometimes genes that we inherit from our parents cause cancer. An example is the BRCA1 gene that causes some cases of breast cancer.