<human>: I have a friend who has recently been diagnosed with breast cancer. What are the most common types of breast cancer?
<bot>: The most common type of breast cancer is invasive ductal carcinoma. This is a form of breast cancer that starts in the milk ducts and spreads to surrounding tissues. It accounts for about 80% of all breast cancers. Other types of breast cancer include lobular carcinoma, which starts in the lobules, and inflammatory breast cancer, which is characterized by an abnormal growth of cells within the breast tissue.