Scientists are constantly uncovering more information about human genes, their sequences, their mutations and the problems that those mutations can cause. As the number of discoveries increases, so do the ideas about how to apply genetic knowledge to help people and improve their lives. One of the newest ideas has been enacted by 23andMe, a company which has historically allowed interested people to uncover their genetic heritage and is now branching into diagnosing genetic mutations.
The system works in the following way: a consumer orders the testing kit online, which is delivered to their home. The kit includes a tube that the person must spit into and mail back in a prepaid box. Tests are run on the DNA extracted from the saliva, and then results are communicated to the customer through a secure online account.
One disease 23andMe has started testing for is breast cancer. The BRCA1 and BRCA2 genes are tumor suppressors, so when they are functioning properly they help to prevent a person from getting cancer. However, mutations to these genes can drastically increase risk of breast and ovarian cancer. Additionally, these mutations can be inherited. It is well-known that having a family history of breast cancer can put you at risk for future diagnoses, and one of the reasons is the inheritability of the BRCA mutations.
A mutation to a gene can happen in a number of different ways. As you probably know from high school biology, your DNA is built of strings of nucleotides, each one including a different base letter: A, T, C or G. If even one of these letters gets switched, replaced or deleted on the BRCA gene, it can lead to harmful outcomes. With that being said, not every mutation is harmful, and genetic testing for breast cancer risk exclusively targets harmful mutations.
The new 23andMe system tests for only three mutations. They are three of the most common ones associated with increased breast cancer risk, but they are certainly not all-inclusive, and this is a source of concern for some.
The problem lies in the interpretation of the results. Though the company is honest about only testing for three mutations, there is great concern that people whose results come back negative will automatically assume they are fine and that they have no mutations to their BRCA gene.
The potential for that response is concerning because it might actually cause a person to undergo fewer mammograms than is recommended, due to the belief that their risk for getting breast cancer is low. It is even more concerning because their risk might actually be high; they might have one of the many mutations that is not accounted for in the test.
Despite these concerns, the Food and Drug Administration (FDA) did approve 23andMe’s genetic testing and recommended that users see a doctor in order to interpret their results. They also reminded patients to continue with their routine breast cancer screenings, as the genetic test is not a replacement for mammograms.
Going forward, these types of tests may become increasingly common, and perhaps there is a benefit that has not been fully considered. In 2017, a study was done to find out how many breast cancer patients who had a BRCA mutation actually knew about it before being diagnosed with cancer. The answer was: not enough. Though around 80 percent of highrisk patients said they wanted genetic counseling and testing, only 40 percent had gotten the counseling and only 50 percent had gotten the genetic test. 23andMe could prove beneficial in alerting patients to potential problems.
Knowledge of increased risks allows people to take charge of their prevention plan. It might not prevent a person from getting breast cancer, but it could lead to preventative lifestyle changes, increased mammography or conversations with a doctor about how to proceed. So perhaps this at-home test is the beginning of how more people will be reached by genetic testing capabilities. In the meantime, eat healthy, exercise, learn how to do a breast self-exam and try to learn more about your personal breast cancer risk, especially if there is a history of the disease in your family.
