New research reveals which genes may increase the risk of breast cancer

In this May 22, 2015 photo, a woman is getting a mammogram at the University of Michigan Cancer Center in Ann Arbor, Michigan. Two large studies published on Wednesday, January 20, 2021 New England Journal of MedicineIt provides a much clearer picture of how hereditary mutations increase the risk of breast cancer in women without a family history of breast cancer, and how common these defective genes are in the general population. Doctors say the results can help women make better decisions about screening, preventive surgery or other steps. (Detroit Free Press via Kimberly P. Mitchell / AP, File)

Two large studies are much clearer about how hereditary mutations increase the risk of breast cancer in women without a family history of breast cancer and how common these defective genes are in the general population. The figure is shown.

Doctors announced the results on Wednesday New England Journal of Medicine It can help women make better decisions about screening, preventive surgery or other steps.

This type of genetic testing is currently not recommended for the general public, but its use is increasing and many people get it from tests that are sold directly to consumers.

New studies show that the risks posed by some genes are “very high,” Mary-Claire King wrote in an email.King, a scientist at the University of Washington, played no role in the new study, but discovered the first breast. cancer Predisposition gene, BRCA1.

“If we are offered the opportunity to learn if every woman is carrying it, we can save the lives of many. mutation It is included in these genes before they are diagnosed with cancer. “

The American Cancer Society estimates that 276,000 new cases of breast cancer were diagnosed in the United States last year. New studies suggest that at least 13,800 of them occur in women with hereditary genetic mutations that increase their risk of developing the disease.

So far, what is known about hereditary risk comes primarily from studies of women with a family history of breast cancer or in unusual situations such as developing breast cancer at a very young age. Also, there are few studies on the specific mutations in these genes and how each affects the probability of developing the disease. New research fills some of those gaps.

One included researchers at the National Institutes of Health, led by Mayo Clinic pathologist Fergus Couch and sponsoring research with the Breast Cancer Research Foundation.

They searched for mutations in 12 genes associated with breast cancer in more than 64,000 women, about half with breast cancer and the other half without breast cancer, part of a particular minority group, such as blacks. We have collected research results from all over the United States, including.

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

“Now we’ve noticed that 2% of women roaming the United States may have mutations in these genes,” Couch said.

There was no difference between racial groups in the overall probability of mutation, but certain mutations were more common in certain groups. For example, black women were more likely to have “triple-negative” cancers associated with tumors that were not fueled by genes targeted by the drug estrogen, progesterone, or Herceptin.

The study also found that mutations in the BRCA1 gene increased the risk of developing breast cancer by about eight times and the BRCA2 gene by more than five times.

Conversely, another gene has been thought to be of great concern, but “what we found is that it’s really low risk … people shouldn’t really act on it. “Couch said.

Actions may include more frequent mammograms or other screening tests, breast or ovarian resection, family tests or other steps.

The new work “provides more accurate risk estimates” to guide such decisions, Couch said.

A second study, led by researchers at the University of Cambridge, England, examined 34 genes. Female Approximately 60,000 people across the UK, Europe, Australia and Asia milk 53,000 similar with cancer and without it.

“They found what we found” — increased certain risks gene And their similar prevalence General populationSaid the couch.

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