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Genetics and Breast Cancer

In developed countries, breast cancer is the most common cancer in women. In the next few years, breast cancer is known to cause more than 500,000 deaths annually. The lifetime risk of breast cancer in developed countries is approximately 10 percent. Approximately 20 percent of cases are diagnosed before the age of 50 years. There are many known factors probably contributing to this disease, these include; genetics, hormones, diet, lifestyle, and other environmental exposures.

At the moment, scientists have identified two genes that contribute to the risk of breast cancer. These are BRCA1 and BRCA2. These two genes are passed from one generation to another if the mutations of breast cancer are already existed in them. Both BRCA1 and BRCA2 are tumor suppressor genes. Their mutations contribute to the risk for breast and ovarian cancers. These genes were initially discovered through number of studies of families with multiple cases of breast cancer in different generations.

BRCA1 is a tumor suppression gene presented on chromosome 17. More than 40 different mutations in BRCA1 have been reported in families at high risk for breast cancer. Women with a BRCA1 mutation are at high risk for developing ovarian cancer. There is significant evidence estimating that approximately 30 percent of women with critical CRCA1 mutation will develop ovarian cancer by age 60 years.

BRCA2 is a breast cancer susceptibility gene on chromosome 13. BRCA2 mutations are known to be associated with a higher risk of male breast cancer and a lower risk of ovarian cancer than are BRCA1 mutations.

Now, these family characteristics may raise suspicion that you might have these genetic mutations and you might want to volunteer for genetic testing. First, you have to ask yourself a list of preliminary questions below:

The closer the relationship between you and your relatives, the higher the possibility, that you might have the mutation. This is true for women with one first-degree relative affected with cancer, as the risk of breast cancer is increased twofold to threefold. If two first-degree relatives are affected, or if the disease was diagnosed in a family member before age 45 years, the risk is even further increased.

If you are interested to learn more about genetic testing, you should consider genetic counseling to find out more about what the information from testing might mean and what effect it might have on a woman and her family. Expert counseling is important whenever genetic testing is undertaken.

Australian family cancer clinics provide a service for people with a family history of cancer and their health professional. If you are interested, you can find out more on www.nbcc.org.au