The Low-Tech Side of Genetic Testing
Finding the genetic underpinnings of diseases is a big part of modern medicine, but the head of the Cleveland Clinic’s genomic institute says the key to identifying your personal risk factors is less genetics and more genealogy.
In this week’s Exploradio, WKSU’s Jeff St.Clair looks at how knowing your family history is the best way to know which genes to watch out for.
Looking for Lincoln's genes
"We had no medical genetics at the Cleveland Clinic before I came in 2005," says Eng. "And now this is the most comprehensive practice of genetics in the country.”
“We got a piece of -- alleged piece -- of the prima donna’s dress where she cradled his bleeding head and tried to extract the DNA,” says Eng.
Unfortunately the blood-soaked swath had been washed and pressed, which destroyed the 150 year-old sample, so, no diagnosis.
"We’re actually waiting for more artifacts that were not ironed and laundered,” she says.
Discovery of cancer-fighting gene
The reason Eng was sought out to solve the Lincoln puzzle is her expertise in identifying cancer genes and cancer preventing genes. Eng was the first to identify a gene called PTEN, a powerful tumor-suppressor, which if altered can have serious consequences.
A PTEN mutation in women, says Eng, can increase the risk of breast cancer "to 85 percent risk instead of the usual 13 percent.”
Mutations in the PTEN gene can also lead to thyroid, kidney, colon and other cancers. Obviously it’s an important risk factor to track. But Eng does not advise anyone to run out and have their genes sequenced.
As head of the Genomic Medicine Institute she recommends a much simpler approach that starts with a visit to your family doctor.
“It’s a very easy screen," says Eng, "They should go in and say, here’s my family health history.”
"It's a triumph of modern medicine."
Cancer prevention begins with family history
Eng says a thorough review of your genealogy is the best way to determine your personal risk of disease. She says that’s because we don’t know, for the vast majority of our 30,000 genes, what any slight alteration might mean for any individual.
“No one should just come and say, 'Look at my whole genome,’" says Eng. "That day is not here," she says, until, "every single variant has a meaning.”
If genetic testing is warranted, genealogy provides the key to interpreting it.
“The family history is very important because often you take the variance in the genes and layer the family history on top.”
Charis Eng is a rare breed. She’s a medical doctor trained in genetic testing, one of only 600 in the country. It’s a combination that she says is saving lives.
“This is what I call gene-informed clinical management, or gene-informed precision medicine."
But genes aren’t everything
Only 10 percent of cancer cases, for example, are caused by inherited genetic mutations.
For most cases, toxins in the environment, stress, diet and countless other factors turn on harmful genes, or turn off helpful ones, like Eng’s cancer-fighting PTEN gene and its cascade of metabolic effects.
“It’s not just PTEN," she says. "It’s PTEN talking to all its buddies downstream, and when the buddies are not behaving, a cancer forms.”
Another avenue of Eng’s research looks at how a chemical in one of her favorite beverages, red wine, boosts the tumor-suppressing function of the gene.
“We show that resveratrol actually increases PTEN levels," says Eng, "and I believe that is one mechanism of why red wine prevents cancer because it upregulates PTEN.”
Moderation in all things
While talking with Eng, it occured to me that when you get down to it, almost anything that you eat, drink, or are exposed to is going to change the way that your body works in some way.
“You are what you eat, remember what grandma said?” Eng quips.
She has another bit of ancient advice.
“At the end of the day today, what should you do?" she asks. She answers herself with the voice of a physician who has seen it all -"Everything in moderation is fine."
So, as you sit down for your next holiday feast, keep moderation in mind, and remember to ask all those questions about your family medical history. It could someday save your life.