Breast cancer refers to a group of diseases where changes in the DNA of cells in breast tissue lead to uncontrolled growth. Such uncontrolled growth usually forms lumps that are either palpable (can be felt) or visible on X-Ray.
Invasive breast cancers usually start in the ducts that carry milk to the nipple (ductal carcinoma) or glands that form milk (lobular carcinoma). Ductal carcinoma in-situ (DCIS) is a form of breast cancer that is a precursor to invasive cancer.
Causes of Breast Cancer
Breast cancers are caused by DNA changes that lead to uncontrolled growth of cells in breast tissue. Most of these DNA changes are sporadic occurrences that cannot be predicted reliably. An inherited genetic predisposition may be found in less than 10% of all breast cancer cases.