Aditya Ashok, MD, MSc

Dr. Aditya Ashok is a gastroenterology fellow at BWH and will be working under the mentorship of Dr. Kyler Staller.. He completed his undergraduate studies at Boston College. Prior to medical school at Harvard Medical School, he obtained an MSc from King's College London on a Marshall Scholarship. He finished his internal medicine residency training in the Osler Medical Residency program at Johns Hopkins Hospital. He plans to pursue an academic gastroenterology career in motility.


Oluwafemi (Femi) Balogun, MBBS, MPH

Dr. Femi Balogun currently works on exploring novel predictive methods for early diagnosis of deteriorating state for neurocritical conditions. He holds a master’s degree in public health (with a major in epidemiology and biostatistics) from Boston University and a medical degree from the University of Ilorin, Nigeria. In his free time, Femi likes to go cycling, take road trips, and visit family and friends. 


Daniel DiGiacomo MD, MPH

Dr. Daniel DiGiacomo is a clinical and research fellow in allergy and immunology at MGH. He joined the CTEU in July 2021 and is mentored by Dr. Hamed Khalili. He received his MD from Tulane University School Of Medicine, MPH in epidemiology from Columbia University, and completed his residency in pediatrics at Children’s National Medical Center. His research interests focus on using inborn errors of immunity as a model to predict treatment responsiveness in refractory inflammatory bowel diseases.


Jonathan Downie, MD

Dr. Jonathan Downie is a clinical and research fellow in Gastroenterology at Massachusetts General Hospital. He is jointly mentored by Dr. Andrew Chan, Dr. David Drew, and Dr. Omer Yilmaz. Dr. Downie’s research interests focus on how genetic, epigenetic, and environmental factors influence the development of gastrointestinal dysplasia and malignancy. Dr. Downie earned an M.D. and Ph.D. (Human Genetics; Advisor: Dr. Lynn Jorde) from the University of Utah School of Medicine where he studied the role of genetic factors in amyotrophic lateral sclerosis pathogenesis and high-altitude physiology. Dr. Downie completed his residency training in Internal Medicine at Massachusetts General Hospital as part of the Stanbury Physician-Scientist Pathway. He plans to be an academic gastroenterologist after completing his training. 

Connor M. Geraghty, PhD

Dr. Connor Geraghty is a Post-Doctoral Research Fellow under Drs. Andrew Chan and David Drew in the CTEU at Massachusetts General Hospital and the Harvard T.H. Chan School of Public Health, Department of Epidemiology. Connor earned his PhD in Nutrition from The Ohio State University where he studied prostate chemoprevention mechanisms of the dietary phytochemical lycopene. Connor's research focus aims centers on the role of pharmaceuticals, diet, and nutrition for chemoprevention with a particular interest in the role of the microbiome during cancer promotion or prevention. 


Jane Ha, MD

Jane Ha is joining CTEU as a post-doctoral research fellow on August 1 and will be mentored by Andy Chan. She received her MD from Korea University College of Medicine in South Korea. Her research interests lie in the epidemiology of gastrointestinal diseases and the translational approach to the investigation of molecular markers.  She will work on projects related to upper gastrointestinal cancer.

Kayla Hartjes, MD

Dr. Kayla Hartjes is a clinical and research fellow in pediatric gastroenterology at MGH. Her research mentors are Dr. Tracey Simon and Dr. Raymond Chung. Her research interests focus on pediatric NAFLD. She received her MD from University of Massachusetts Medical School. She plans to go on to be a pediatric transplant hepatologist and work in academic medicine. 

Xinwei Hua, PhD, MPH

Dr. Xinwei Hua is Research Fellow at MGH CTEU mentored by Dr. Hamed Khalili. Her current research interest is the interplay of environmental factors and molecular characteristics in the pathogenesis of inflammatory bowel disease. 

She is a trained molecular epidemiologist and received her MPH from Emory University and her doctoral degree from the University of Washington and the Fred Hutchinson Cancer Research Center. Her previous research centers around inflammation and colorectal cancer survivorship.

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Ming-ming He, MD

Dr. Ming-ming He is a postdoc in Dr. Mingyang Song’s group. She is an attending medical doctor from the Sun Yat-sen University Cancer Center (SYSUCC), specializing in gastrointestinal (GI) cancer, both diagnosis / treatment and research, as well as a collaborative, studious medical oncologist with a strong medical background, passionate about cancer epidemiology, and translating cancer research into cancer prevention and control.

Hanseul Kim, PhD

Dr. Hanseul Kim is a postdoctoral research fellow at CTEU in the Massachusetts General Hospital and Harvard Medical School. She is co-mentored by Drs. Long Nguyen, Andrew Chan, and Curtis Huttenhower. Dr. Kim earned her PhD degree in Population Health Sciences, focus on epidemiology, from the Harvard Graduate School of Arts and Sciences and Harvard T.H. Chan School of Public Health where her thesis topic was on vitamin D, calcium, and early-onset colorectal neoplasia. Hanseul’s current research interest centers on studying the gut microbial communities related to gastrointestinal conditions, especially colorectal cancer.

Minsik Kim, BS, MS, PhD

Minsik is a postdoctoral researcher in the Lai lab and CTEU. He graduated with his BS, MS, and PhD degree at the Korea Advanced Institute of Science and Technology (KAIST). During his prior postdoctoral fellowship, he became fascinated by the microbiome when studying how microalgae treatment of wastewater reduces pathogenic bacteria through competitive microbe-microbe interactions. On holidays, he loves riding something with wheels such as bikes, cars, Segways, and skateboards.ol.

Etienne Nzabarushimana, PhD

Dr. Etienne Nzabarushimana joins the CTEU as a post-doctoral research fellow in Dr. Long Nguyen's group with co-mentorship from Dr. Andrew Chan and Dr. Curtis Huttenhower. Etienne recently graduated with a PhD in Informatics from Indiana University.


Georgios Polychronidis MD,, M.Sc.

Dr. Georgios Polychronidis is a postdoctoral research fellow in the Department of Epidemiology in the Harvard T.H. Chan School of Public Health. He is mentored by Dr. Mingyang Song. He graduated from the University of Ioannina Medical School and after joining the Heidelberg Transplantation Center for a research fellowship he completed his general surgery residency at the Department of General, Visceral and Transplant Surgery at the University Hospital Heidelberg. During his training he was a research scientist at the Study Center of the German Surgical Society and studied clinical trial management at the Beuth University of Applied Sciences. His research is mainly focused on evidence-based surgery and liver disease. Dr. Polychronidis has been awarded a two-year research fellowship from the German Research Foundation (DFG) to investigate the link between liver disease and colorectal neoplasia.


Eric Przybyszewski, MD

Dr. Eric Przybyszewski is a clinical and research fellow in gastroenterology at MGH.He received a BS from Cornell University and an MD from Columbia University.He was a House Officer at MGH where he completed his internal medicine residency.He completed clinical research training through the Harvard T.H. Chan School of Public Health's Program in Clinical Effectiveness. His research interests are in the coagulation changes associated with chronic liver disease.He plans to be an academic transplant hepatologist.


Chatpol Samuthpongtorn, MD

Chatpol (Jamie) Samuthpongtorn joined the CTEU on July 1, 2022 as postdoctoral fellow mentored by Dr. Andrew Chan and Dr. Raaj Mehta. He received his MD from Chulalongkorn University in Thailand. He was selected to be the scholar of the Prince Mahidol Award Youth Program, a highly prestigious honor. His research interests include the role of the gut microbiome and metabolomics in the pathogenesis of dementia, depression and acute ischemic stroke.

Magdalena Sevilla, PhD

Magdalena Sevilla is a postdoctoral researcher in Dr. Alissa Manning’s Lab. She received her master’s and PhD degree in Science at National Autonomous University of Mexico (UNAM). Magdalena is passionate about solving population health problems related to the highly prevalent metabolic diseases, particularly type 2 diabetes and its interaction with obesity and environmental factors. Her current research interest is in using mathematical models and complex biostatistics methods to integrate genetic, metabolomic, and environmental factors to understand the molecular mechanisms that underlie the risk to develop type 2 diabetes.

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Michaela Tracey, MD

Dr. Michaela Tracey is a clinical fellow in Pediatric Gastroenterology at Boston Children's Hospital and a research fellow in the Harvard-wide Pediatric Health Services Research Program. She joined the CTEU in August 2021 and is mentored by Dr. Hamed Khalili. Her research focuses on social determinants of health and outcomes in inflammatory bowel disease. She received her MD from the University of Massachusetts Medical School and completed her residency in pediatrics in the Boston Combined Residency Program in Pediatrics, based at Children's Hospital and Boston Medical Center. 


Eugenia Uche-Anya, MD, MPH

Dr. Eugenia Uche-Anya is a second-year gastroenterology fellow at MGH. She joined the CTEU in August 2020 and is mentored by Dr. Andrew Chan. She earned an MD at Columbia University and an MPH from Harvard School of Public Health. She is interested in population health outcomes and health disparities, especially in patients with gastrointestinal cancers and chronic liver diseases.

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Hannah VanEvery, PhD

Dr. Hannah VanEvery is a postdoctoral research fellow in the CTEU at Massachusetts General Hospital and the Harvard T.H. Chan School of Public Health, Department of Nutrition. She is co-mentored by Drs. Long Nguyen, Andrew Chan, and Curtis Huttenhower.  Dr. VanEvery earned her PhD in Nutritional Sciences and Clinical and Translational Science from The Pennsylvania State University where she studied dietary and metabolic risk factors for rheumatoid arthritis. Hannah’s current research centers on the role of dietary factors and gut microbial communities in inflammatory bowel disease.

Liang Wang, MD

Dr. Liang Wang is a gastrointestinal surgeon from the First Affiliated Hospital of Sun Yat-sen University, China. He joined the CTEU at MGH and Harvard T.H. Chan School of Public Health in 2018 as a research fellow under the mentorship of Dr. Mingyang Song. His research interests include risk factors of colorectal cancer and the relationship between biomarker of fatty acids and colorectal serrated polyp and conventional adenoma.

Yiqing Wang, PhD

Yiqing Wang is a research fellow in the CTEU, working in Dr. Andrew Chan's research group. She received a BS in Biochemistry from the University of Virginia and a PhD in Nutrition Epidemiology from the University of North Carolina at Chapel Hill. Her current research interests include the roles of diet, genetics, metabolomics, and gut microbiome in the pathogenesis of colorectal cancer, inflammatory bowel disease, and cardiovascular diseases.  


Robert (Rob) Wilechansky, MD

Dr. Rob Wilechansky is a current gastroenterology fellow at MGH and is mentored by Dr. Tracey Simon and Dr. Raymond Chung. Rob graduated from Williams College and received his MD from Columbia University. He completed residency training and Chief Residency at Boston University Medical Center. He is a former AASLD Emerging Liver Scholar and Ambassador and plans to pursue transplant hepatology fellowship in the future. Rob’s research interests lie in the epidemiology of nonalcoholic fatty liver disease, dietary influences, and factors underlying progression to cirrhosis.

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Keming Yang, MD, PhD

Dr. Keming Yang is a postdoctoral research fellow co-mentored by Dr. Andrew Chan, Dr. Yin Cao, and Dr. Kyle Staller in the CTEU at MGH. She received her medical degree in clinical medicine from Nanjing Medical University, Nanjing, China, PhD in epidemiology from Indiana University, Indianapolis, IN, and prior research training from Harvard T.H. Chan School of Public Health, Boston, MA. Her current research interests focus on environmental factors, molecular markers, as well as their interplay in the pathogenesis of chronic digestive diseases and colorectal cancer using data from large cohorts and trials.