Test yourself: Which of these three cancer myths is a fact?

Cancer is not contagious -- myth or fact? Some cancer is caused by contagious viruses, like HIV. So in a way, you can catch cancer. You can't directly swap cancer through bloodstream, saliva, or germs, but you can pass along some of the organisms that could cause cancer in a roundabout way. This is especially true for cervical and liver cancers, as well as some lymphomas.

Benign tumors should always be left alone -- myth or fact? Benign tumors don't have cancer cells, but they can still be dangerous. That's because tumors can grow large enough to block the pathway of important nutrients, or put pressure on critical organs. For example, even though many brain tumors will never spread, they are still removed.

If you're diagnosed with cancer, you need treatment right away -- myth or fact? Even though some cancers spread quickly, it's always smart to get a second opinion. Good doctors will encourage you to get one to confirm that the diagnosis is correct. The best second opinion comes from a doctor at a different institution than where the first doctor practices, and one that is well regarded in cancer treatment. After that, see someone that specializes in the type of cancer involved, because he or she will have a better handle on the different courses of treatment.