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Dr. Juanita Merchant: A researcher to be reckoned with

Get to know our AGA Research Foundation researcher of the month, someone who has made significant strides in the detection of gastric cancer.

Juanita Merchant, MD, PhD, is a renowned gastroenterologist whose contributions to the understanding of chronic inflammation and its association with gastric cancer have been called game-changing. She has built a remarkable career that spans more than two decades. Early on, she received the 1998 AGA-R. Robert & Sally D. Funderburg Research Award in Gastric Cancer from the AGA Research Foundation. That funding was key to her career. Dr. Merchant was able to intensify her investigation into how chronic inflammation can drive cancer cell growth in the upper gastrointestinal tract, possibly changing physicians’ approach to diagnosis and treatment. As we reflect on her trailblazing research, which originated at the University of Michigan, Ann Arbor, and now continues at the University to Arizona in Tucson, we celebrate Dr. Merchant as our AGA Research Foundation researcher of the month.

Dr. Merchant, a professor of medicine in the University of Arizona department of medicine and chief of the division of gastroenterology and hepatology, used the AGA grant to focus on an important signaling pathway that regulates gastric acid levels in the stomach. The Merchant lab AGA-funded project specifically focused on exploring how Hedgehog signaling regulates gastric homeostasis and when dysregulated contributes to gastric cancer. Building on this research over the years, Dr. Merchant has identified potential biomarkers for gastric cancer in chronic Helicobacter-infected patients’ blood. If physicians are aware that a patient’s Hedgehog-regulated immune cells in the stomach are supporting the development of gastric cancer, then they can begin to monitor the individual more closely to detect the disease at an early stage.

Gastric cancer is the fourth most common malignant disease and the second leading cause of cancer-related death worldwide. In the United States, more than 26,000 people were diagnosed with the disease in 2018, according to the National Cancer Institute.

“Colon cancer gets a lot more attention than gastric cancer,” Dr. Merchant says. “We do colonoscopies to look for colon cancer, which has led to reduced mortality. But we don’t screen for gastric cancer. Some people never come to a physician because they have no symptoms.”

By the time patients report blood in the stool, a hallmark symptom, the cancer may be advanced and the prognosis poor, Dr. Merchant says. Identifying biomarkers for cancer could improve diagnosis, prognosis, and treatment.

“If we see that patients are getting into trouble, we can monitor them more closely. It’s like a needle in a haystack — who will go on to develop cancer? Some people come in with an upset stomach or have some family history of cancer, but we don’t assess them unless they have blood in stool or vomiting. So having a biomarker for cancer is critical — these tests are non-invasive and really inexpensive. Then we do more expensive tests to follow that up. It helps us make decisions about whether we need to investigate patients further.”

Dr. Merchant’s AGA Research Foundation grant has laid the groundwork for a 15-year grant from the NIH and another subsequent grant so she can further explore whether immune cells recruited to the stomach to fight a bacterial infection triggers inflammation in the stomach, possibly causing cancer. For her groundbreaking work in this area, Dr. Merchant was presented in 2017 with the American Gastroenterological Association’s Distinguished Achievement Award in Basic Science.

Meenakshi Rao and son


Dr. Merchant hosting a cooking class for patients at the University of Arizona. The Cookin’ Docs motto, “Eat your guts out!”

When she isn’t in her lab, or collaborating with Asian scientists in Japan and China, Dr. Merchant is hosting cooking classes sponsored by the University of Arizona to educate patients about the importance of a healthy diet. She plans to collaborate with local chefs to help patients choose and prepare foods that are nourishing and palatable.

“We roll up our sleeves and go through it with them,” she says. “We want patients to understand the impact that their diet and the environment have on their GI health.”

The AGA Research Foundation funds investigators today so that clinicians have better patient care tools tomorrow. Support the future of patient care with a tax-deductible contribution to the AGA Research Foundation. Donate today at

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