Normal Breast Tissue

The breast is made up of two tissue types, glandular and stromal tissues. The glandular tissue contains lobules and ducts. The cells of the lobules make milk in women who are breast-feeding. This milk is carried to the nipples through the ducts.

The lobules and ducts are lined by cells that are gradually replaced to maintain a healthy lining. Normal breast cells will have a uniform size and shape. Cancer develops when an abnormal cell produces millions of copies of itself.

Initially the cancer cells are confined to the area lining the ducts. This is called Ductal Carcinoma in Situ (DCIS). After a period of time the cancer cells can move out of the ducts to the surrounding tissue area. This is called Invasive Breast Cancer.

Cells enter the small lymph vessels and veins that run through the breast. Lymph nodes are connected to the lymph channels and act as filters trapping the cancer cells. The lymph nodes are the first site at which the cancer cells spread beyond the breast. Eventually the cancer cells can bypass the lymph nodes and travel to other areas of the body with good blood supplies typically the liver, lungs and bone marrow.