Being a woman whose mother (and my mother's sister) is a breast cancer survivor, and being that cancer has taken two of my father's sisters and recently a beloved uncle (who was also Sir's godfather), I know just how important this question is. For those struggling with cancer personally or by way of caring about someone who has it, this site is a great resource for answering the question, which goes without saying, but I will answer it, emphatically...
You can also find www.IsMyCancerDifferent.com on Twitter (http://twitter.com/#!/ismycancerdiff).