Doctors can seldom explain why one woman gets breast cancer and another doesn't. It is clear, however, that breast cancer is not caused by bumping, bruising, or touching the breast. And this disease is not contagious; no one can "catch" breast cancer from another person.

Scientists are trying to learn more about factors that increase the risk of developing this disease. For example, they are looking at whether the risk of breast cancer might be affected by environmental factors. So far, scientists do not have enough information to know whether any factors in the environment increase the risk of this disease.

Some aspects of a woman's lifestyle may affect her chances of developing breast cancer. For example, recent studies suggest that regular exercise may decrease the risk in younger women. Also, some evidence suggests a link between diet and breast cancer. Ongoing studies are looking at ways to prevent breast cancer through changes in diet or with dietary supplements. However, it is not yet known whether specific dietary changes will actually prevent breast cancer. These are active areas of research.

Scientists are trying to learn whether having a miscarriage or an abortion increases the risk of breast cancer. Thus far, studies have produced conflicting results, and this question is still unresolved.

Research has led to the identification of changes (mutations) in certain genes that increase the risk of developing breast cancer. Women with a strong family history of breast cancer may choose to have a blood test to see if they have inherited a change in the BRCA1 or BRCA2 gene. Women who are concerned about an inherited risk for breast cancer should talk to their doctor. The doctor may suggest seeing a health professional trained in genetics. Genetic counseling can help a woman decide whether testing would be appropriate for her. Also, counseling before and after testing helps women understand and deal with the possible results of a genetic test. Counseling can also help with concerns about employment or about health, life, and disability insurance.