New studies clarify which genes may raise breast cancer risk

Two large studies are giving a much clearer picture of which inherited mutations raise the risk of breast cancer for women without a family history. Also, the studies are helping us understand how common these genes are in the population.

The American Cancer Society estimates that 276,000 new cases of breast cancer were diagnosed in the United States last year. The new work suggests that at least 13,800 of them occur in women with inherited gene mutations that raise their risk of developing the disease.

The results of the studies were published in the New England Journal of Medicine. Doctors say the results of the studies can help women and their primary care physicians make better decisions about screening and preventative steps such as surgery.

The study concludes, “until now, what has been known about inherited risk largely has come from studies of women with a family history of breast cancer or unusual situations such as getting it at a very young age. There also has been little work on specific mutations in these genes and how much each affects the odds of developing disease. The new studies fill some of those gaps.”

One of the two new studies was led by Fergus Couch, a pathologist at the Mayo Clinic and was sponsored by the Breast Cancer Foundation.

In the study, any mutations in 12 genes that have been tied to breast cancer in more than 64,000 women, about half with the disease and half without it, pooling results from studies throughout the United States including some in specific minority groups such as African American.

They found troublesome mutations in about 5% of women with the disease and in 1.63% of the comparison group.

“Now we realize that 2% of the women walking around in the United States might have mutations in these genes,” Couch said.

The study also found having a mutation in the BRCA1 gene raised the risk of developing breast cancer nearly eightfold, and in the BRCA2 gene, more than fivefold.

The BRCA gene is linked to several different types of cancers including: cervical cancer, renal cell carcinoma, ovarian cancer, renal cell carcinoma, leukemia, and head and neck cancer. There is currently not enough evidence to link BRCA mutations to other types of cancer, but many medical practitioners believe that it may be possible. The BRCA genes can be inherited through genetics from one or both parents. For women who have a history of multiple types of cancer in their family, there is an increased risk that they will develop BRCA, although there is currently no studies that indicate whether or not men will develop the condition as well.

Conversely, another gene has been thought to be very concerning but “what we found is that it’s really low risk … people really shouldn’t be acting on it,” Couch said.

The second of the two studies were led by research and doctors at the University of Cambridge in England. This study looked at looked at 34 genes in women throughout the United Kingdom, Europe, Australia and Asia—about 60,000 with breast cancer and 53,000 similar ones without it.

“They found what we found”—increased risk from certain genes and a similar prevalence of them in the general population, Couch said.

What does this mean for you?

Genetic testing can further the information on the genes you or a loved one carry. Research shows that genetic testing can help your provider recommend more precise treatment options. Genetic testing can also help you determine whether you (or your loved one) are at an increased risk for breast cancer and how to improve the prognosis. 

Vita Medical Solutions is proud to partner with laboratories to facilitate access to advanced hereditary cancer (CGx) genetic testing.

Learn more about your personal and family genetic makeup and personalized medicine options through our genetic test offerings. Read more specifically about CGx testing here:

With qualifying insurance, this test can cost you nothing out of pocket. Click below to schedule a call with one of Vita Medical’s Patient Services Consultants to find out your eligibility.

Call us 1.800.590.9292 (toll free) or email at [email protected].

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Read the full article here: https://medicalxpress.com/news/2021-01-genes-breast-cancer.html