Genetic testing and Breast Cancer
By Kristine Smith
As published in the Loveland Reporter Herald Healthline Magazine, October 2013:
October is Breast Cancer Awareness Month, which is an annual campaign to increase awareness of this deadly and debilitating disease. About 12% of women in the general population will develop breast cancer at some point during their lives. The key, in many cases, is early detection. This includes self- exams and annual mammograms, and in some cases, genetic testing. The genetic testing through a simple blood test is proving to be increasingly popular but is not without its controversy, both in terms of the financial cost and in terms of accuracy. For many women, when Angelina Jolie revealed in the spring that she had her breasts removed after discovering she had the breast cancer gene it came as a wake-up call. Since the news, area hospitals have seen a surge in requests from women seeking genetic testing to determine their breast cancer risk.
A doctor or genetic counselor can order the tests, called BRCA1 or BRCA2, which can range in price from $300-3000. Insurance may or may not cover the cost of this test. However, with a strong family history of breast or ovarian cancer, the results can be telling and crucial to both the patient and the patient’s children. When a woman inherits a harmful BRCA1 mutation, the above statistic jumps to 55-65% and those who carry the BRCA2 mutation; this number climbs to 45% by the age of 70. About 1.4 percent of women in the general population will develop ovarian cancer sometime during their lives. By contrast, according to the most recent estimates, 39 percent of women who inherit a harmful BRCA1 mutation and 11 to 17 percent of women who inherit a harmful BRCA2 mutation will develop ovarian cancer by age 70.
The testing looks for genes identified as BRCA-1 and BRCA-2 that mark an increased risk of developing breast cancer, up to 50 to 80 percent. The results of these tests are used to determine treatment options in patients already diagnosed with breast cancer and to help those not yet diagnosed with cancer to consider preventative treatment options. Genetic testing, which has become a more widespread practice in local hospitals over the past five years, is also becoming more affordable , thanks to a Supreme Court ruling creating competition among labs that perform the testing, and more widespread insurance coverage. The U.S. Supreme Court ruled in the spring that the human genome could not be patented, essentially opening up competition in genetic testing. Previously, a lab called Myriad Genetics was performing nearly all of the testing in the country. Getting coverage for the testing continues to be a challenge for some patients, but local cancer care providers said it is becoming more widely accepted by insurance companies.
BRCA1 and BRCA2 are human genes that produce tumor suppressor proteins. These proteins help repair damaged DNA and, therefore, play a role in ensuring the stability of the cell’s genetic material. When either of these genes is mutated or altered, DNA damage may not be repaired properly. As a result, cells are more likely to develop additional genetic alterations that can lead to cancer. These inherited mutations have been associated with female breast and ovarian cancers and have been associated with other types of cancers as well. A harmful BRCA1 or BRCA2 mutation can be inherited from a person’s mother or father. Each child of a parent who carries a mutation in one of these genes has a 50 percent chance of inheriting the mutation. The effects of mutations in BRCA1 and BRCA2 are seen even when a person’s second copy of the gene is normal. A woman’s lifetime risk of developing breast and/or ovarian cancer is greatly increased if she is shown to have inherited this mutation.
It is also important to note that other characteristics of a particular woman can make her risk higher or lower than the average risks. These characteristics include her family history of breast, ovarian, and, possibly, other cancers, the specific mutation she has inherited and other risk factors, such as her reproductive history. However, none of these other factors is as strong as the effect of carrying a harmful BRCA1 or BRCA2 mutation.
Science has made great strides in identifying genetic causes of many cancers in recent years and while this particular testing may not be foolproof, it is a simple way to test for a predisposition to a complex cancer that strikes thousands each year. See your doctor today for further information on this important genetic testing and don’t forget to schedule an annual mammogram.