Breast cancer is one of the most common cancers among American women. Over 250,000 women in the United States will be diagnosed with breast cancer this year.
Breast cancer usually starts in glands or ducts that produce and store milk in the breasts. It can be diagnosed by the patient if a lump is felt in the breast. Mammographic diagnosis is preferred as the cancer is usually in an earlier stage when picked up this way - hence the potential benefit of "screening" mammograms. If left unchecked, the cancer can spread to other parts of the body, usually to the lymph nodes under the arm on the affected side first, but also to any other part of the body, especially the bones. Understanding where cancer is in the body, called staging, is critical to planning the best therapy
The current outlook for breast cancer depends on the "stage" when it is diagnosed. If diagnosed early, the cure rate approaches one hundred percent.
The current thinking is that most breast cancers are caused by alterations in a cell’s genomic make-up, including DNA, RNA, and proteins. Specifically, increases in "oncogenic" proteins, that drive cancers, or decreases in "tumor suppressor" proteins, which help to prevent cancer, are operative in many breast cancers. Oncogenes are much like a gas pedal in that they determine how quickly or slowly the cell will grow. Tumor suppression genes are the body’s natural defense against cancer. Approximately twenty percent of breast cancers show an increase in the HER2 oncogenic protein, while many show a decrease in the BRCA tumor suppressor protein. This latter driver of breast cancer is particularly important because it can be inherited. In other words, some patients are pre-destined to develop breast cancer, with lifetime risks of up to eighty-five percent. If a patient with cancer is genetically tested and is found to have an inherited risk factor, such as a BRCA mutation, their children can be regularly tested to find small tumors at a curable stage. It should be stressed, however, that most cases of BRCA alteration in breast cancer are NOT inherited.