Breast cancer is a disease in which malignant (cancer) cells form in the tissues of the breast.
A family history of breast cancer and other factors increase the risk of breast cancer.
Breast cancer is sometimes caused by inherited gene mutations (changes).
The use of certain medicines and other factors decrease the risk of breast cancer.
Signs of breast cancer include a lump or change in the breast.
Tests that examine the breasts are used to detect (find) and diagnose breast cancer.
If cancer is found, tests are done to study the cancer cells.
Certain factors affect prognosis (chance of recovery) and treatment options.