Lexington resident Chao Zhang has won a $2.2 million federal grant to study why a common stomach bacterium causes cancer in some people but not others.

Zhang, an assistant professor of computational biomedicine at Boston University's Chobanian & Avedisian School of Medicine, received the five-year R35 award from the National Institutes of Health's (NIH) National Institute of General Medical Sciences, according to a Boston University announcement. The grant funds his work building artificial intelligence tools to track how bacteria in the human gut interact with the body over time.

The research centers on Helicobacter pylori, a bacterium that infects nearly half the world's population, according to the National Cancer Institute (NCI). People carrying H. pylori are six times more likely to develop stomach cancer than those without it, and nearly 90 percent of gastric cancers are linked to the infection. Yet only a small fraction of those infected ever get sick.

Zhang told the Lexington Observer that some people carry the H. pylori infection for 40 years without developing cancer, while others develop gastric cancer after 10 to 20 years. He said his team wants to understand why the same infection affects people so differently.

Stomach cancer is the fourth most common cancer worldwide and the second leading cause of cancer death globally, according to the NCI.

Zhang's NIH-funded project has two main tracks. In one, his team collaborates with researchers at Weill Cornell Medicine to study how microbiomes in the stomach interact with surrounding tissue, aiming to understand how upper gastrointestinal cancers develop and how they might be caught earlier.

In the second track, Zhang's team works with physicians at Boston Medical Center. They are exploring whether a patient's microbiome profile can predict response to immune checkpoint inhibitor therapy, a type of cancer treatment.

Zhang didn't start in science. He earned a bachelor's degree in automation from Beijing Institute of Technology and spent about five years as a software engineer, including at Samsung. He later pursued a PhD in computer science at the University of Missouri, where he began studying bioinformatics under Professor Dong Xu. Postdoctoral work at Weill Cornell Medicine drew him into gastric cancer and microbiome research.

His BU lab has collected 50 gastric cancer samples and 106 gastric endoscopy biopsies from a non-cancer population. BU describes the dataset as the largest non-cancer gastric genomics study ever conducted.

Zhang moved to Lexington with his family in 2022 when he joined BU. His two children attend Lexington Public Schools. He told the Lexington Observer he chose the town for its quiet character, rich history and strong schools.