Misinterpreting cancer genetic test results or resulting in unnecessary surgery

The United States “New York Times” on March 24 detailed disclosure of the actress, director Angelina Jolie Pitt using surgical removal of ovarian decision. Her practice may be right – Jolie has a family history of breast and ovarian cancer and is found to carry a gene mutation that is known to strongly increase the risk of developing cancer. The researchers point out that her story will inspire other women to try cancer-related genetic testing, but some people may find themselves in a state of uncertainty.

Researchers record a surge in the need for genetic testing after Jolie disclosed in 2013 that she had carried a dangerous mutation in the BRCA1 gene and had undergone a preventative bilateral mastectomy. They call it the Angelina Jolie effect. However, not every person pursuing genetic testing will have a clear course of action.

Thousands of mutations in BRCA1 and related BRCA2 genes are likely to increase women’s cancer risk. However, it is difficult to say whether these mutations will cause someone to develop cancer, because the researchers do not have enough evidence that their effects are statistically valid.

These mysterious mutations are called variants of unexplained significance. And they are a headache – because it’s hard to tell whether a person needs to take action on them, for example, for preventive surgery.

“The standard in this area is that you should not make decisions based on things we do not understand,” says Fergus Couch, a cancer geneticist at the Mayo Clinic in Rochester, Minn. “This is very complicated,” says Couch. You get cancer and you want to know more, so it ‘s hard to blame each other.

One may not realize that some laboratories are more likely than other laboratories to find mutations in which the latter can not explain its meaning.

For years, Riad Genomics Inc. of Salt Lake City, Utah, had dominated the BRCA gene test in the United States. A ruling by the US Supreme Court in 2013 allows other companies to do the same, but Riad Genomics still has more data on how mutations can improve cancer risk than any other company in the world. As a result, the researchers estimate that the company reported only 2% to 3% of unidentified variants, compared with 10% of unidentified variants found by other companies.