What are some misunderstandings about breast cancer risk factors?

There are a number of misconceptions about what can cause breast cancer. These include, but are not limited to, using deodorants or antiperspirants, wearing an underwire bra, having a miscarriage or induced abortion, or bumping or bruising breast tissue. However, none of these factors has been shown to increase a woman's risk of breast cancer. In addition, cancer is not contagious; no one can "catch" cancer from another person.

This answer is based on source information from the National Cancer Institute.