©Pregnancy bliss 2008
BRCA1 and BRCA2 and other genes
Many women would have heard of the genes called BRCA1 and 2. These are actually normal genes and are not a risk factor. Everybody has them. In some cases, however, these genes undergo mutation and it is that alteration that ratchet up the risk for breast cancer. The gene mutation can then be inherited through generations and this is where family history becomes important.
The lifetime risk of an average woman to get breast cancer is estimated to be 1 in 8. For a woman with BRCA1 or 2 gene mutations, the risk is increased dramatically to about 1 in 3, sometimes much higher. These are the individuals who need to be identified by the screening programs to enable them to get individualized surveillance.
Researchers have been busy trying to identify other rogue genes that might be responsible for individual women’s increased risk of breast cancer. In May 2007, the journals Nature and Nature Genetics published results of an international collaboration research which had identified 4 common genes which, when mutated, increased the risk of breast cancer to some degree (not as high as BRCA1 and BRCA2 mutations). It is believed there are many more yet to be discovered.
Techniques for identifying the gene mutations are getting increasingly refined and there is hope that in a decade or so, universal genetic screening might be possible. This will allow for targeted surveillance for those identified as being at increased risk of developing breast cancer. It will also allow a more accurate quantification of the degree of each individual’s risk.
A woman carrying the BRCA1 or 2 mutation has her lifetime breast cancer risk increased from 1 in 8 to 1 in 3 (33%) but sometimes as high as 85%