Siyan “Stewart” Cao, MD, PhD

Siyan “Stewart” Cao, MD, PhD

Instructor in Medicine

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  • Fellowship: Washington University School of Medicine, St. Louis, MO (2022)
  • Residency: University of California San Francisco, CA (2019)
  • MD: Columbia University, New York, NY (2016)
  • PhD: University of Michigan, Ann Arbor, MI (2013)


Dr. Cao joined the faculty of Division of Gastroenterology at Washington University in July 2022. Dr. Cao was born in Chengdu in Southwestern China. After college at Zhejiang University, China, Dr. Cao entered the PhD program in Biochemistry at the University of Michigan, Ann Arbor. He then moved to New York where he obtained MD at Columbia University. Afterwards, he completed his residency in internal medicine at the University of California San Francisco and gastroenterology fellowship at Washington University in St. Louis. Dr. Cao’s research interests are in the mucosal immunity and precision medicine in inflammatory bowel disease. His clinical interests include colon cancer screening, gastrointestinal bleeding, microscopic colitis, dysphagia and gastroesophageal reflux disease.

Research Interests

My research interests are in the basic and translational medicine in inflammatory bowel disease (IBD), particularly mucosal immunity, endoplasmic reticulum stress, and gut microbiome in intestinal inflammation. Using advanced cell culture and mouse models, I have characterized cellular stress pathways that play essential roles in innate lymphoid cells (ILCs) in intestinal homeostasis. I am also interested in IBD-related conditions whose etiologies are poorly understood, such as Crohn’s disease of the pouch and perianal fistulizing Crohn’s disease. Using single-cell techniques, I have revealed unique immune responses that may contribute to the pathogenesis of those conditions. Another focus of my research is to identify reliable biomarkers that predict response to IBD therapies including IL-23 antagonists.

Research Publications

Please click here for my NIH Bibliography.