By Sara Tiner
Your genome on a thumb drive? Family-sourcing health data? Endometrial Cancer and Bacteria? Those were a few of the precision medicine highlights discussed at the April 27 Center for Individualized Medicine (CIM) Open House, where the topic was "Changing Lives Through Research."
Exponential Growth in Technology
Surrounded by new, CIM-focused exhibits in the Mayo Clinic Research Information Center of the Gonda Building lobby, Scott Beck, associate administrator for the CIM, kicked off the open house. He outlined the history of DNA discovery from the structure of the double helix to the base pairs that make up the rungs of the helix ladder, as well as the progress of genetic sequencing from the ability to decode roughly 1000 bases a day to 40 billion bases in an hour.
But even with the technological advances, Beck said, “We are essentially in the first chapter of a very long book.”
Future chapters may include innovations like blood tests for cancer recurrence or to determine fetal genetics, replacing invasive amniocentesis. You may even be able to sequence your genome at home using a drop of blood and a sequencer the size of a thumb drive.
Genomic Interpretation is a Limitation
But interpreting that information, according to CIM genetic counselor Teresa Kruisselbrink M.S., C.G.C., is another matter. In her talk at the CIM open house, Kruisselbrink clarified that current commercial genomic tests are generally limited to rare genetic conditions caused by genetic changes in one gene.
“Most of these conditions are pretty rare,” she said. “Most of us are unlikely to have these disorders in our lifetime.” The more common diseases like coronary artery disease, diabetes and most cancers are more complex, she explained. They result from environmental influence and numerous genetic changes, each which adds a small bit of risk and makes the genetic aspect harder to identify.
The Original Database: Family
So how do we determine where each person’s individual risk lies for these diseases? “One of the most important tools we use is family history,” Kruisselbrink said. Family history is the health story of your siblings, parents, and extended family. It included diseases that your family members lived through, died from, and the ages at which these events took place (create your own family history with this online tool).
“When I’m looking for high genetic risks, I’m looking for unusual presentations of diseases,” explained Kruisselbrink. Two examples are Alzheimer’s disease in a person under age 65, or breast cancer at a young age, which may have a genetic link to hereditary breast and ovarian cancer. “When we find these patterns in the family, sometimes we simply make recommendations for screening,” she continued. “For those where we think there’s a strong genetic risk we might do genetic testing.”
One word of caution though; families aren’t very good at knowing exactly what type of cancer each person had.
“It’s not something that a lot of families talk about over Thanksgivings,” said Kruisselbrink. “If someone tells me their aunt had stomach cancer I wonder if it was endometrial, ovarian, or stomach; so I suggest getting the medical records if you can, or asking the person closest to that family member for medical information.”
Microbiome Influence on Health
But individualized medicine is more complex than the genome. It includes the unique mix of micro-organisms that live on and in each one of our bodies, called our microbiome. Purna Kashyap, M.B.B.S., and Nicholas Chia, Ph.D., whose research is covered in a recent Discovery’s Edge article, as well as associate consultant to the microbiome project Marina Walther-Antonio, Ph.D., who studies the vaginal microbiome, explained how they examine the role of microbes in healthy living and disease causation.
Endometrial Cancer and Bacterial Influence
Dr. Walther-Antonio studies complications related to pregnancy, like preterm labor which is characterized by bleeding and inflammation. Her work implicated the vaginal microbiome in these outcomes, and she says, “We started thinking what if there’s something with endometrial cancer since there’s bleeding and an inflammatory profile.”
Endometrial cancer is the fifth most common cancer, according to Dr. Walther-Antonio, and usually affects postmenopausal women around age 60. A key symptom is bleeding after a woman has entered menopause.
Dr. Walther-Antonio and her team compared bacterial communities within the uterus of cancer patients to non-cancer patients to see if there were any distinct differences between the two groups.
“Quite surprisingly there actually was,” she said. “There was a very clear signal not only in the uterus but in the vagina.”
Bacterial Bad Actors
Two microbes were associated with endometrial cancer: Atopobium and Porphyromonas. Atopobium is already associated with preterm labor, bacterial vaginosis and facilitation of infection by other bacteria like HIV and HPV. Less is known about Porphyromonas, according to Dr. Walther-Antonio, but its “cousin” Porphyromonas gingivalis lives on gums and causes bad breath, gingivitis, and tooth decay.
“So what we think is happening,” explained Dr. Walther-Antonio, “is that they work together to disrupt the cell machinery that can then lead to cancer. We don’t know that but it’s our theory. And we know they are there with endometrial hyperplasia, which is a precancerous condition so if they are taking advantage of the situation then they’re doing it pretty early on.”
Which is a good time to look at treatments. Dr. Walther-Antonio suggested some treatments might be directly targeting the microbes or even a vaccine for postmenopausal women. But those targets are still in the future.
Transforming Promise into Practice
This common theme throughout the CIM open house was the promise of precision medicine. But changing the promise into practice for most patients is still a challenge.
“In most families we are not able to provide treatment that will have an impact on the care of a patient,” said Beck. But even without a treatment, individualized medicine helps patients and families prepare, plan, and promote scientific advancement. “Being able to understand the problem is almost, in many cases as important as being able to address the problem,” he said, “because it allows you to network with other people who have had similar experiences and provides a social network of others.”
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Sara Tiner is a science writer supporting research and education within Public Affairs at Mayo Clinic.
The Center for Individualized Medicine display is open to the public and located at the Research Information Center in the lobby of the Gonda Building, Mayo Clinic, Rochester, Minnesota. The Research Information Center is open from 8 a.m. to 5 p.m. Central time, Monday through Friday. The display will run through 2016.
Tags: center for individualized medicine, Dr. Marina Walther-Antonio, Dr. Nicholas Chia, Dr. Purna Kashyap, Endometrial cancer, Family History, individualized medicine, Mayo Clinic Research Information Center, microbiome, Precision Medicine, Sara Tiner, Scott Beck, Teresa Kruisselbrink, Uncategorized, vaginal microbiome