Understanding Breast Cancer Genes
3 Min. Read | October 14, 2021
Add These Three Breast Cancer Genes to Your Vocabulary
Your priority To-Do list may not have “get a mammogram” on it if you don’t have any relatives who have had breast cancer. You might want to rethink that. Half of women who carry genetic changes putting them at increased risk for breast cancer don’t know it and don’t fit current clinical guidelines for getting genetic testing.
Estimates show as many as 360,000 women in the U.S. are struggling with inherited forms of breast cancer today. Around 28,000 new cases are diagnosed each year. Women with inherited forms of breast cancer tend to be diagnosed at a younger age than other forms of the cancer, often under the age of 50.
Good Genes Gone Bad
Some genetic variants can increase risk of breast cancer by as much as 85 percent. In 2013, the American College of Medical Genetics issued a list of 56 genes – since updated to 59 – that were clearly associated with disease and were actionable—through medical intervention, screening and lifestyle changes, you could reduce the risk. That list contains the two most well-known breast cancer-associated genes, BRCA1 and BRCA2.
To most women those acronyms spell evil. But the non-mutated versions are really “good guys.” They help repair damaged DNA or destroy cells if DNA cannot be repaired. When harmful variants make them defective in getting this done, cancer can develop. No one knows why these genes are particularly active in breast and ovary tissue, but they clearly are. The actual variants that cause the defect vary widely and tend to differ between ethnic groups.
Earlier this year the ACMG added 14 more genes to its actionable list, including a third for breast cancer, PALB2. That acronym makes clear its role in cancer. It stands for Partner and Localizer of BRCA2. Variants in PALB2 convey risk similar to that associated with BRCA2, which is just slightly lower than BRCA1.
Knowing you have inherited risk can be the first step to saving your life
Many oncologists believe genetic testing for the three breast cancer-associated genes should be more widespread. It can be the first step to more frequent screening, both via mammograms and MRI. The increased risk is so dramatic, many women consider proactive prophylactic mastectomy.
The New York Times recently ran a story about the value of extending genetic screening to include PALB2. Both the National Comprehensive Cancer Network and the ACMG issued guidelines suggesting that women with PALB2 variants have MRIs and mammograms on an alternating basis every six months as with the other breast cancer genes.
“The reality is we are all at risk for something, it’s just whether we have that line of sight. It’s a real awareness issue,” Dr. Peter Hulick of Northshore University Hospital in Evanston, IL told the Times.
GoodCell’s genetic predisposition test screens for harmful variants in genes on the ACMG59 list including BRCA1 and BRCA2. We are currently finalizing the process needed to expand that offering to the recently updated ACMG73 including PALB2, the third critical breast cancer-associated gene. It’s easy to find out your genetic status and actions you can take by joining GoodCell.