Finding Risks, Not Answers, in Gene Tests

Jennifer was 39 and perfectly healthy, but her grandmother had died young from breast cancer, so she decided to be tested for mutations in two genes known to increase risk for the disease.

When a genetic counselor offered additional tests for 20 other genes linked to various cancers, Jennifer said yes. The more information, the better, she thought.

The results, she said, were “surreal.” She did not have mutations in the breast cancer genes, but did have one linked to a high risk of stomach cancer. In people with a family history of the disease, that mutation is considered so risky that patients who are not even sick are often advised to have their stomachs removed. But no one knows what the finding might mean in someone like Jennifer, whose family has not had the disease.

It was a troubling result that her doctors have no idea how to interpret.

Such cases of frightening or confusing results are becoming more common because of a big recent change in genetic testing for cancer risk. Competing companies have hugely expanded the array of tests they offer, in part because new technology has made it possible to sequence many genes for the same price as one or two. Within the next year, at least 100,000 people in the United States are expected to undergo these tests. The costs, about $1,500 to $4,000, are covered by some, but not all, insurers.

Various efforts are underway to interpret mutations and compile them in publicly available databases; one of the latest is an online registry to which patients can upload their own data. Eventually, they will be able to see how many other people have the same mutation, and how many get cancer. Called Prompt, for Prospective Registry of Multiplex Testing, it was created by Memorial Sloan Kettering, the University of Pennsylvania, the Mayo Clinic and the Dana-Farber Cancer Institute. Several genetic testing companies are also helping to promote it.

Link to full article

Originally published in The New York Times