Leigh Greathouse Career Award: Linking Diet and Cancer Treatment

Among the many challenges cancer patients navigate during treatment is a particularly unpleasant side effect called Chemotherapy-Induced Diarrhea (CID). This condition, suffered by approximately 50 percent of all colon cancer patients, is a malady that can negatively impact their battle against the disease and even be fatal.

Currently, there are no known biomarkers to indicate a person’s susceptibility to CID, nor any preventative therapies. Leigh Greathouse, Ph.D., assistant professor in human sciences and design, aims to change that.

Greathouse, herself a cancer survivor and a leading researcher in the relationship between diet, the microbiome, disease and health, has received a Career Development Award from the Department of Defense (DoD) aimed at discovering both biomarkers and potential determinants of the condition.

“Our goal is to identify bacteria in the gut and dietary factors that are predictive biomarkers of CID,” Greathouse says. “On top of that, identifying the mechanisms and bacteria that are potentially causative of CID—how does what you eat prior to starting chemotherapy affect the bacteria that live in your gut, and how do those bacteria predict your response to chemotherapy?”

A Personal Journey

At just 24 years of age, Greathouse experienced unusual stomach pains which proved to be the symptom of something much deeper—stage IV uterine leiomyosarcoma. That diagnosis led her on a journey through six rounds of chemotherapy and multiple surgeries before finally hearing the words “cancer-free.” Even after overcoming the disease, lingering gastrointestinal (GI) issues caused by her surgery forced a continued fight through illness and discomfort. In the midst of that battle, she recognized a correlation that would eventually become a calling.

“I noticed that when I changed from eating ‘comfort food’ to food I knew was healthy and anti-inflammatory, I had a dramatic improvement in my energy,” Greathouse recalls. “This really drove home the importance of diet in response to cancer therapy. Also, my long-term battle with GI issues after my cancer treatment was over really focused my attention on preventing and alleviating GI issues during and after cancer treatment.”

In 2006, the study of the relationship between the diet, gut and disease began to galvanize after technological advances made it easier for researchers to identify microbes for study. Over the next few years, Greathouse would focus on these issues while receiving her Ph.D. from the University of Texas M.D. Anderson Cancer Center, a Masters of Public Health at Johns Hopkins University and serving as a postdoc researcher at the National Cancer Institute in Bethesda, Maryland.

After completing her postdoctoral fellowship at the National Cancer Institute, Greathouse began her work at Baylor. Here, she established the Laboratory of Health and Human Behavior to conduct groundbreaking research into microbiome and cancer.

The Career Development Award, valued at $480,569, will enable Greathouse to take that research further for the benefit of colon cancer patients.

Improved Treatment and Quality of Life

For colon cancer patients, CID represents more than a temporary discomfort or a burden to their daily life. CID can actually impact their course of treatment—severe CID can force a stoppage in chemotherapy, which can extend the length of treatment; still others must lower their chemo dosage, which can impact effectiveness. Sadly, many patients continue to suffer GI complications for years or even decades after remission that significantly reduce quality of life.

“There are really no tools to collect dietary data from people going through chemotherapy. You can imagine, on a day-to-day basis, a patient’s diet changes depending on how well they feel or don’t feel,” Greathouse said, “We’re going to be piloting that in this study. From there, we will analyze dietary data to search for trends that might be associated with the prevalence or severity of Chemotherapy-Induced Diarrhea, response to treatment and long-term gastrointestinal symptoms.”

The DoD grant will enable Greathouse to enroll and collect data from over 100 patients with stage-two or stage-three colon cancer, in partnership with the Baylor Scott & White McClinton Cancer Center in Waco and Baylor Scott & White Medical Center in Temple. On the project, she will work with Baylor research mentors Touradj Solouki, Ph.D., professor of chemistry, Ramon Lavado, Ph.D., assistant professor of environmental science and Lucas Wong, M.D., hematologic oncologist at Baylor Scott & White.

Greathouse and her research team will collect data from patients on their dietary intake, analyze data on microbes in their gut at the time of diagnosis, and collect dietary intake and gut bacteria from stool samples for analysis throughout chemotherapy. In partnership with longtime collaborator Jun Chen, Ph.D., of the Mayo Clinic, Greathouse will utilize machine learning, a type of artificial intelligence, to analyze vast amounts of data and develop algorithms to identify biomarkers or predictive biomarkers that can help clinicians and patients better treat and manage colon cancer therapy.

“We’ll be looking to see if there is any correlation between the microbiome gut analysis, and if there are specific metabolites or bugs that actually correlate with the prevalence or severity of CID,” Greathouse said.

“I'm most intrigued to understand if how you've been eating over the past year affects how you respond to treatment, because there are indications that it should. Does your diet leading to treatment affect how you're going to respond? Does your diet during treatment dictate how you respond? Right now, there’s very little evidence and very little data to help dietitians understand whether or not changing somebody's diet is going to help them respond better or not to treatment. It would be very meaningful to find that out, and to be able to help patients eat in such a way to help them respond better to treatment.”

Culture of Collaboration

Greathouse’s Career Development Award adds to an impressive year for faculty earning such honors. In the spring, four other colleagues earned CAREER grants from the NSF. Five such awards in one year represents a new high for the University.

“The recent increase in the number of career award winners clearly demonstrates that we are hiring well in a variety of disciplines, and we are building a strong foundation for future success and sustainability of our research enterprise,” Kevin Chambliss, Ph.D., Vice Provost for Research, said. “I fully expect that the success of this year’s career award winners will increase our ability to recruit top talent in the future, which will further accelerate our progress toward R1.”

Greathouse, who came to Baylor in 2015, has seen the University’s increased focus on meaningful research, codified in the strategic plan of Illuminate to pursue R1 research status, accelerate a culture of collaborative research that leads to more impactful work.

“It's really supportive. Having the option to collaborate with multiple people around campus who do a variety of work is very helpful for my research, because it gives me a lot of strengths that I can pull from that I don't necessarily have myself. You don’t get that everywhere,” Greathouse said. “Awards like the career grant are critical to demonstrate that and put Baylor on the map nationally—we have the resources and the talent to execute and address important issues.”