Many of you already know all about genetic testing for breast/ovarian cancer, but I recently saw this quite good primer from the Komen Foundation. More than 90% of all breast cancers are NOT due to a genetic mutation, but, instead, are called "incidental" breast cancers. This likely explains why the overwhelming majority of women with breast cancer have no family history of the illness, and it surely explains the level of frustration we all have in trying to figure out the cause(s). My non-scientific belief continues to be that breast cancer happens due to some combination of genetic vulnerability and environmental contamination. This is much more complicated than blaming cancer on insecticides or dry cleaning fluid, and means that it takes (I think) both our bodies and the world around us to create a cancer. Our bodies actually have many built in systems to try to prevent a gene from mutating and going cancer beserk (thought you would like the scientific language).
As we know, our bodies are composed of billions of cells, each with a specific design and purpose. In every one of those cells, there are genes composed of DNA that contain the operational blueprint for that cell. When there is an alteration or mutation of a gene, the cell's behavior is impacted. Mutations can cause a positive or a negative change in the gene. Scientisits first discoved the BRCA1 gene in 1994; when it is working normally, it actually suppresses the abnormal growth of breast cells. Mutations in the BRCA1 gene can stimulate the growth and are associated with genetic or familial breast or ovarian cancers. There are three known gene mutations that can cause these diseases: BRCA1, BRCA2, and the so-called "Jewish breast cancer gene", 185delAG. Very recently, there have been discoveries of a number of additional genes whose mutations are seen in women with breast cancer. Although there is now screening for these additional genes (for women with a positive personal or family history who have tested negative for the usual three), there is little known about their meaning.
Here is the start of the Komen information and a link to read more:
What is genetic testing for breast cancer and who should get it?
Most breast cancers are not related to genes or family history. In fact, only five to 10 percent of all breast cancers diagnosed in the U.S. are thought to be hereditary.
However, if you have been diagnosed with breast cancer, you may worry about the risk to your family members. And, if a family member has been diagnosed, you may worry about your own risk. So, who really needs to be concerned about this and who should consider genetic testing? Furthermore, if you do have a breast cancer gene mutation or a strong family history, what can you do to lower your risk of developing breast cancer?
Talking to your health care provider is the best way to understand your (or your family's) risk of hereditary breast cancer. Here, we cover the basics of hereditary breast cancer and genetic testing to help you discuss these topics with your provider.
Genes and gene mutations
Every cell in your body contains genes. Genes contain the blueprints (genetic code) for your body.