We answered questions you sent us about personal genomic testing and the Supreme Court’s recent decision barring companies from patenting genes. To boil down the complicated science into real-world advice, we asked the chairwoman of the Cleveland Clinic Foundation’s Genomic Medicine Institute, Charis Eng, M.D., Ph.D., to give us—and you—the lowdown on how the research and ruling will affect health care.
1. Personal genomic testing sounds like something out of a sci-fi novel. What is it, exactly?
Our genes are like a code that tells our bodies to develop and function according to a certain set of instructions. We inherit much of this code from our parents. (The environment we live in plays a role as well.) Science has evolved to the point where companies can now test a person’s whole genome—his or her DNA gene inheritance—for certain traits, ancestry, how the person may react to specific drugs and inherited disease risk (such as for Parkinson’s or breast cancer, for instance). The results are then marketed and sold to consumers in order to help tailor prevention tactics and treatments that might reduce the risk of disease. One well-known genomic testing company, 23andMe, allows individuals to order kits, send in their saliva for testing and obtain the results themselves (rather than through their doctors).
That’s the short version. In truth, there are many things to consider and understand about genomic testing. Quick science lesson: When your sample arrives in the lab it is tested for single nucleotide polymorphisms (SNPs), accidental variations in your DNA that have been associated with diseases. Some SNPs track closely with disease risk, whereas others don’t. Most medical experts recommend that any increased risk of disease, or an association, should be confirmed with additional tests or your family history and discussed with a physician geneticist—someone trained in the field of genetics. On the flip side, negative risk (decreased risk of disease), or no association, should not be interpreted as lack of risk, as it could provide false reassurance. Why be so cautious with the interpretation of results? Because most conditions and diseases have a number of causes that can influence their development—genetics is only one factor to consider in the overall risk for disease. (One exception: SNP analysis to evaluate the risk for adverse drug reactions is often quite accurate.)
2. Can you explain the recent Supreme Court decision on whether human genes can be patented? And what did it have to do with Angelina Jolie?
This past June the Supreme Court ruled that human genes (DNA sequences) exist naturally and therefore cannot be patented—in other words, no person or company can “own” a human gene and sell products/services related to that gene. This specific case was about the genes BRCA1 and BRCA2—when those genes have a mutation, they significantly raise a woman’s risk for breast cancer and ovarian cancer. The Utah-based company Myriad, based on its research, had obtained patents on those genes and was marketing an expensive test that detected the genes’ mutations in women. The Supreme Court ultimately sided with the American Civil Liberties Union and other plaintiffs who had brought the suit against the company, and threw out patents held by Myriad. The ruling applies not only to BRCA1 and 2, but also to thousands of other gene patents held by companies, including genes associated with colon cancer, Alzheimer’s disease and muscular dystrophy.
The test gained national attention after actress Angelina Jolie revealed that her decision to undergo a preventive double mastectomy was the result of testing positive for one of those mutations. (On average, those with a BRCA1 mutation have a 65 percent risk of developing breast cancer; after the double mastectomy, Jolie’s risk dropped to less than 5 percent.)
3. Is the inability of companies to patent genes a good or bad thing for patients?
Patients and doctors generally view this as a good thing because it should lead to many companies and universities being able to offer gene testing in a competitive environment. When Myriad held an exclusive patent on the genes, no other entity could offer BRCA1/2 testing, leading to a monopoly and high pricing. And if that weren’t inhibiting enough, more than 40 other companies had patents on disease-associated genes. So to do whole genome testing, a testing agency would’ve needed contracts with all those companies, and the cost would be prohibitive. Now whole genome testing can soon be provided for much less. This change will also make research into disease prediction much more possible. (Myriad’s and other companies’ patents required that researchers pay them to do research on the genes.) Overall, this is a great decision for promoting research, and within 10 years or so, should help people learn what they need to do most to prevent higher risk conditions.
4. So should I or any of my family members undergo genomic testing?
It depends. Most of your genetic linkage can be determined from your family history, so knowing your family history and sharing that with your doctors is the first step and is often more important than genetic tests when it comes to most diseases. Jolie wouldn’t have had the tests in the first place if she hadn’t had a family history of cancer—her mother died of ovarian cancer and her aunt died of breast cancer.
Another thing to consider is that genomic testing is still an evolving science. Many exciting things are happening in the field, but we’re still in the early stages of learning about how our genes affect our risk of disease, so it’s not something that experts recommend across the board. Regardless of whether your doctor recommends genomic testing for you, one of the most important things you can do is to take your health into your own hands and make choices about living in ways that will help prevent cancer. For example, we know that sitting in the sun for long periods without sunscreen is the equivalent of sending an engraved invitation to cancer. When it comes to smoking, there is such a direct correlation between smoking and cancer that you might as well inject cancer cells right into your body. Tobacco doesn’t just increase lung cancer, it’s also been shown to increase the incidence of bladder, prostate and breast cancers.
By following guidelines for keeping your heart and arteries young, you’re also following a good prescription for preventing cancer. Obesity and inactivity have been linked to cancer, so eating a reasonable-calorie diet with the right foods and getting regular physical activity are paramount for keeping your whole body healthy.
If you have heart disease in your family, you’ll really want to pay attention to your lifestyle: If a parent or other close family member developed coronary artery disease before age 60, your chances are significantly higher than the average person’s of developing it. Abnormalities in lipid production—that is, a tendency to have higher LDL levels and lower HDL—can be passed down right along with things such as baldness, freckles and height.
All that said, you shouldn’t discount the advances in medicine and the importance of having your health monitored by a professional to help you tailor a program for disease prevention as well as disease detection. Even though preventing the onset of disease is the ultimate goal, there’s no guarantee you will succeed—bad luck and genes are still important determinants in your life (and we don’t want you to carry guilt along with the disease). So the next best goal after prevention is early detection, which exponentially increases your chance of survival when diagnosed with any disease.