The direct-to-consumer genetic testing market has helped tens of millions of Americans not only learn their family lineage, but also given them a microscopic view of their health.
Popular DIY tests, such as Ancestry DNA and 23&Me, offer a variety of kits depending on how deep you want to go into your DNA, and range from $99 to $200.
Kits that analyze your cheek swab for health markers can reveal genes that indicate a higher likelihood of breast, ovarian and prostate cancer, helping customers (whether or not they have a family history of cancer) better understand their risk individual.
But oncologists warn that home tests are not for everyone.
Direct-to-consumer testing is fairly limited in scope when it comes to the variants they test. 23&Me, for example, only analyzes 44 genetic variants in the BRCA1 and BRCA2 genes, which suggest a susceptibility to breast cancer, but there are more than 4,000 known variants that increase risk.
23&me also tests for two variants in genes that increase the risk of colorectal cancer, although about 25 acquired genetic mutations are known to increase the risk of CRC.
Dr. Mikkael Sekeres, a blood cancer expert at the University of Miami, advised concerned customers to contact their doctors for a more comprehensive lab test rather than trying an at-home test first.
He added that only a small proportion of cancers (between five and 10 percent) are thought to be associated with genetic variants, while the rest are caused by lifestyle and environmental factors such as smoking and air pollution. , which calls into question whether these tests are really the glass. ball that people want.
And doctors also warn that many people without scientific training may misinterpret their results or exaggerate something, leading to even greater anxiety.
Popular DNA tests, such as those conducted by ’23andMe’, can reveal certain genetic mutations inherited from our parents that may indicate cancer risk. But doctors fear these results could cause excessive stress and anxiety. And many people will not benefit
Dr. Sekeres told Washington Post Doctors typically only order a specific test based on whether the information from those tests will actually lead to a significant difference in your care.
If they know that the risk of disease is low and that it may cause additional costs and stress to the paint, they may skip it.
He said: “When it comes to home testing, I advise my patients to think this way like a doctor.”
If the results are negative, the person will probably breathe a sigh of relief and their stress will end there, although that negative result does not mean that they will never get cancer.
But if the test comes back positive, how might that change your daily life, Dr. Sekeres asked.
Will you tell your children about your genetic predisposition? Will you reduce your alcohol consumption and quit smoking to minimize your risk? Will you follow a strict healthy eating regimen and exercise for 30 minutes or more a day? Will you remember to slather on sunscreen every day before leaving the house?
Dr. Sekeres said, “If the answer to these questions is ‘no,’ you probably should not order the test.”
According to the National Cancer Institute, people who discover that they do not carry a genetic variant that other members of their family can give birth to ‘Survivor’s guilt,’ which can cause extreme embarrassment and a false sense that a negative outcome could have been avoided.
And inconclusive results can cause uncertainty and stress.
There is also the risk of false-positive results, which can lead to stress and the financial cost of obtaining appropriate follow-up tests ordered by a doctor.
A 2018 report revealed a staggering 40 percent of raw data coming from direct-to-consumer genetic testing. produced false positives.
And just because a test result may show a certain mutation does not mean that the person is destined to develop cancer, although it does indicate an increased risk.
Anyone who sees a mutation in the BRCA1 gene, for example, will probably become very distressed. Having a BRCA mutation does not mean that cancer is a foregone conclusion. Rather, having the mutation increases cancer risk by 45 to 85 percent.
Home tests, which take into account a person’s ethnic origin, have another major drawback: They only look for changes in DNA passed from parents to children. But genes can undergo important changes throughout our lives.
About 90 percent of cancer mutations occur during a person’s lifetime due to factors such as aging, environmental stressors, and random errors in cell division and growth, compared to about 10 percent for cancer genes. cancer transmitted from our parents.
Dr. Sekeres stated, “It can take decades to acquire the mutations that cause cancer, which is why most cancers are diagnosed in older adults, with a median age of 66 in the United States.” .
Home genetic tests only detect genetic mutations inherited from our parents, although the vast majority of cancers are caused by mutations that occur throughout a person’s life.
Only three to five percent of colorectal cancer cases are related to an inherited genetic change. Meanwhile, the remaining 95 to 97 percent are caused by acquired mutations.
Between five and 10 percent of breast cancer cases are believed to be hereditary, meaning they result directly from genetic changes. That means that about 90 percent of cases are caused by acquired mutations.
But the BRCA1 and BRCA2 genes are perhaps the best-known mutated genes that increase women’s susceptibility to breast and ovarian cancer, as well as prostate cancer in men.
About 1 in 400 people in the general population carry one of these genes, but the rate is higher among people of Ashkenazi Jewish descent, with about 1 in 50 people affected.
Mutations in the MLH1, MSH2, MSH6 and PMS2 genes can cause colorectal, gastric, ovarian and endometrial cancer and are colloquially known as Lynch syndrome. Nearly one in every 300 people has one of these mutations.
And TP53, which leads to a wide range of conditions including breast, bone, soft tissue, brain, adrenal gland and blood cancers, is known as Li-Fraumeni syndrome. Approximately one in 5,000 people have inherited this variant.
Of those three, 23&me only tests for BRCA mutations.
Dr. Sekeres said, “If you test positive for a genetic mutation, the good news is that while genetic mutations can put us at higher risk of developing cancer, there are interventions we can take to mitigate that risk.”
“Talk to your doctor about the best plan for you, which may include early screening and taking medications such as oral contraceptives or aspirin.”