Breast Cancer

Breast cancer is the most common cancer in women. The challenge in this illness is to diagnose it as early as possible. Mammogram and frequent breast exams by the individual as well as their physicians are the current methods of early detection.

There are, however, certain women who are at higher risk of developing breast cancer; those with a positive family history of breast cancer. About 10-20% of breast cancer patients have a positive family history for either breast cancer or other cancers. Genetic testing can help family members of women with breast cancer to assess their risk of developing a cancer. If one's mother or sister or aunt has been diagnosed with this cancer, the individual can certainly be tested and counseled about the potential risks of developing cancer. Aberrations in BRCA1 and BRCA2, that are tumor suppressor genes, may be seen in majority of patients with inherited breast cancer. Such cases occur much earlier in life, in 4th decade, as opposed to non-genetic form of cancer that occurs in 6-7th decade of life. The cumulative risk of breast cancer for women with BRCA1 and BRCA2 approaches 87% by age of 85 years, meaning 87% of these women will develop breast cancer by the age of 85. In a group of 403 women with BRCA1 mutation, 209 had developed breast cancer ( 52%) only with the average age of 42-43 years at the time of diagnosis an ranging from 19-96 years of age) and 40 (10%) women developed Ovarian cancer and 22 ( 5%) developed both cancers. In the same group, 132 women (33%) had not developed either cancer. There is substantial variation in the risk of developing cancers with these mutations. There are various forms of mutations and each may have a specific risk associated with it. It would take many decades to gather more accurate statistics for each individual mutation of BRCA1 or BRCA2.

Harboring these genes predisposes majority of women to ovarian cancer as well as breast cancer. At least 15-20 % of individuals with a mutation of BRCA1 gene do not develop cancer. Such people are predisposed to the illness, yet may never develop it; there might be other factors other than this single gene that determine who would and would not develop a cancer. On the other hand, women who have already developed a breast cancer and test positive for BRCA1 mutation have a higher risk for development of a another breast cancer as well as developing other cancers, such as ovarian cancer and colon cancer.

Other gene abnormalities can also predispose women to breast cancer; p53, CD1 and ATM mutations. Identification of women carrying the breast cancer susceptibility genes will help them to develop a strategy as to confront this illness way ahead of time. BRCA1 was cloned in 1994 and since then, many hundred different mutations (aberrations) have been discovered.

Those who test positively for a BRCA1 or BRCA2 may explore any of the following options to reduce their risk of developing breast cancer:

Chemoprevention (usage of certain medications with the goal of reducing the cancer risk) This method is being studied looking into certain drugs like Tamoxifen and other similar compounds.

Prophylactic Surgery ( removal of breasts or ovaries) Some studies have shown that removal of both ovaries can even significantly reduce the risk of breast cancer in this group of patients.

Why to test?	Genes and Cancer	Available Tests
Breast Cancer	Ovarian Cancer	Colon and Rectal Cancer
Rare Cancers	Cancer Syndromes	Who needs to be tested?
Prostate Cancer	Discrimination	Costs
Family Issues		Other Issues