Genetic Testing: Do We Really Want to Know?
In a recent article for the Financial Times, David Crow details how cancer has deeply affected his family: five family members, including his mother, have died of cancer.
Hereditary cancer tests like those offered by Myriad Genetics make it possible for individuals like David to analyze their genes for defects known to contribute to higher cancer risk – allowing them in some cases to take preventative measures to actively combat or prepare for the possibility of cancer. Angelina Jolie, for example, was tested by Myriad Genetics in 2013. When she discovered a mutation in the BRCA1 gene that greatly increased her risk of developing breast and ovarian cancer, she chose to have a preventative double mastectomy and her ovaries and fallopian tubes removed.
Genetic testing isn’t all blood tests, though. Genetic counseling services are also provided by scientists trained to assess the risk of disease based on family history. A detailed family tree is developed, which the individual must present to a medical professional who is qualified to decide whether or not to order the hereditary cancer test. If the test is ordered, a few vials of blood are drawn and sent to Myriad, where the DNA will be extracted and sequenced. Twenty-eight “cancer-related” genes are then tested for abnormalities, which are categorized as deleterious (mutated, high cancer risk), benign (mutated but not known to increase risk), or uncertain.
The BRCA1 gene sequence was first discovered by Myriad founder Mark Skolnick in 1994, but only in recent years have more scientific discoveries and links between genetic defects and diseases been revealed. Other companies and institutions are searching for ways to identify biomarkers that could be predictive of illness.
GRAIL, a McKesson Ventures portfolio company, is researching genetic sequencing with the ultimate goal of developing of a blood test for early cancer detection – long before the terminal stage is reached. The development of such a test would make it possible for individuals to routinely be screened for cancer instead of discovering it late stage.
If you have a Financial Times subscription, you can read Crow’s full article here.