Breast Cancer: The Basics

What is the breast?

The breast is a collection of glands and fatty tissue that lies between the skin and the chest wall. The glands inside the breast produce milk after a woman has a baby. Each gland is also called a lobule, and many lobules make up a lobe. There are 15 to 20 lobes in each breast. The milk gets to the nipple from the glands by way of tubes called ducts. The glands and ducts get bigger when a breast is filled with milk, but the tissue that is most responsible for the size and shape the breast is the fatty tissue. There are also blood vessels and lymph vessels in the breast. Lymph is a clear liquid waste product that gets drained out of the breast into lymph nodes. Lymph nodes are small, pea-sized pieces of tissue that filter and clean the lymph. Most lymph nodes that drain the breast are under the arm in what is called the axilla.