Lab Members

Allan Tsung, MD | Professor and Principal Investigator

Allan Tsung, MD, is a surgical oncologist and scientist focused on liver, bile duct, and pancreatic cancers. His work sits at the intersection of surgery and immunology, where clinical questions drive laboratory discovery and new therapies move back to patients.

As he often says, “I am both a surgeon and a scientist. As a surgeon, it’s important to know what questions need to be answered to better treat our cancer patients. And as a scientist, my role is to study and gain new knowledge needed to answer those questions.”

His commitment to cancer research began early after losing his father to the disease. “The treatments back then were unable to cure my father,” he reflects. “That was unacceptable to me.” This urgency continues to shape his work today.

Dr. Tsung’s lab studies the tumor microenvironment and develops strategies to make cancer more vulnerable to therapy. He seeks trainees and collaborators who are curious, rigorous, and motivated to translate discovery into meaningful impact for patients.

Hongji Zhang, PhD | Assistant Professor

As a cancer immunologist, my research revolves around understanding the role of the tumor microenvironment in various oncologic disease processes, such as colorectal cancer and liver cancer; and providing novel strategies for prevention and cure, especially the role of inflammatory responses with treatments such as immune therapy.

Samantha Ruff, MD | Assistant Professor

Samantha Ruff, MD, is a surgical oncologist who specializes in treating gastrointestinal (stomach, colorectal, appendix, small bowel), pancreas, liver, and biliary cancers. She started the cytoreduction surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) program at UVA for metastatic cancer to the peritoneum. Her research focuses on the immune tumor microenvironment and improving the efficacy of immune checkpoint inhibitors in metastatic colorectal cancer.

Dr. Ruff grew up in New York and studied molecular and cellular biology at Johns Hopkins University. She was part of the inaugural class at Hofstra University’s Zucker School of Medicine. She completed her general surgery residency at Northwell Health, where she received multiple awards for clinical and professional excellence. During her residency, she spent two years at the National Institutes of Health (NIH) studying the tumor microenvironment and creating novel pre-clinical models. While at the NIH, she served as the administrative chief fellow and received an award for clinical excellence. Dr. Ruff recently completed a fellowship in complex general surgical oncology and hepatopancreatobiliary surgery at The Ohio State University prior to joining UVA as an Assistant Professor in September 2024.

Chengli Shen, MD, PhD | Associate Professor

My research expertise spans biostatistics, bioinformatics, and biological studies related to vascular disease, kidney diseases, infectious diseases, cancers, and surgical outcomes. I have collaborated closely with biological researchers and clinical investigators from diverse Departments of Surgery, engaging in study design, data analysis, manuscript preparation, and grant applications. My contributions have been integral to multiple grants funded by NCI, DoD, NIAID, and AHRQ.  

Xinghua Liao | Lab Manager

Xinghua Liao serves as the laboratory manager for the Tsung-Zhang-Ruff Research Group, contributing her wealth of experience and expertise in laboratory management, research methods, and administration. She plays a vital role in the team, overseeing daily lab operations, facilitating lab growth, and implementing innovative strategies to streamline workflow within the group. 

Elio R, Bitar MD | Postdoctoral Research Associate

Elio Bitar, MD, is a postdoctoral research associate in the Tsung-Zhang-Ruff Research Group. He received his undergraduate and medical degrees from the American University of Beirut and subsequently moved to Charlottesville, where he joined the Department of Surgery at UVA. His research focuses on gastrointestinal and hepatopancreatobiliary surgical oncology, with particular emphasis on outcomes, frailty and risk stratification, health services research, and the use of large clinical databases and real-world data to inform perioperative care and quality improvement in surgery

Yiyu Zhang, PhD | Research Scientist

Dr. Yiyu Zhang is a research scientist in the Tsung-Zhang-Ruff Research Group. He earned his PhD from Southern Methodist University, where he investigated neuroinflammation and apoptosis in neurodegenerative diseases such as Huntington’s disease and Alzheimer’s Disease. Following his PhD, Dr. Zhang completed a postdoctoral fellowship in the Department of Molecular Physiology & Biophysics at the University of Virginia. His postdoctoral research focused on developing and utilizing genetically encoded fluorescent and bioluminescent sensors to study various diseases, including cancer, Alzheimer’s Disease, and diabetes. In 2024, he joined the Tsung-Zhang-Ruff Research Group, where he now concentrates on exploring the role of immune cells in the progression of metabolic dysfunction-associated fatty liver disease (MAFLD) to hepatocellular carcinoma (HCC).

Xiao Cui, MD, PhD | Visiting Scholar

Xiao Cui, MD, PhD, is a Chief Physician in Surgery at The Second Clinical College of Anhui Medical University, where he serves as Deputy Director of the Department of Surgery Teaching and Research Office and Teaching Director of the Surgical Residency and Resident Training Program. He specializes in hepatobiliary and liver transplantation surgery, with extensive experience in complex abdominal surgery and perioperative management.

Jian Han, MD, PhD | Visiting Scholar

Dr. Jian Han is a visiting scholar in the Tsung-Zhang-Ruff Research Group. He earned his MD degree from Tongji Medical College, Huazhong University of Science and Technology in China. Following his MD, he worked as a physician in the Department of Gastroenterology at the Tongji Hospital, Huazhong University of Science and Technology in China. In 2025, he joined the Tsung-Zhang-Ruff Research Group, where he now concentrates on exploring the role of B cells in the progression of metabolic dysfunction-associated steatotic liver disease (MASLD).

Kaelyn Cummins, MD | Surgery Resident

Kaelyn Cummins, MD is a general surgery resident at the University of Virginia working in the Tsung-Zhang-Ruff Research Group. She is originally from Maryland but received her medical degree from Baylor College of Medicine before coming back to the East Coast. She is studying the interaction of immune therapies with the tumor microenvironment, disparities in surgical outcomes, and the genetic basis of common surgical diseases. She is also working towards a master’s degree in clinical research.

Olivia Sears, MD | Surgery Resident

Olivia is a general surgery resident at the University of Virginia currently in the Tsung-Zhang-Ruff Research Group. She received her undergraduate degree from Northeastern University and medical degree from the University of Massachusetts. She has experience in translational immunology and has worked on drug development from bench to bedside. Olivia is currently in her first year of research investigating new targets for immunotherapy and looking at the immunological effects of histotripsy, a type of focused ultrasound treatment.

Janice Oh | Medical Student

Janice Oh is a medical student at UVA in the class of 2027 who spent the summer following her first year working in the Tsung-Zhang-Ruff Research Group studying the effects of preoperative exercise on liver metastases and resistance mechanisms of colorectal cancer. She is interested in pursuing a career in surgical oncology.

Sana Aziz | Undergraduate Student

Sana Aziz is an undergraduate student in the College of Arts and Sciences, Class of 2028, pursuing a major in Biology. She joined the Tsung-Zhang-Ruff Research Group in Spring 2025. Outside of the lab, she volunteers at a local free clinic and serves as President of a student organization focused on humanitarian aid. Sana is interested in how scientific research translates into clinical practice and plans to pursue a career in medicine.

Songhan Pang | Undergraduate Student

Songhan Pang is an undergraduate student at the University of Virginia in the Class of 2026 majoring in Human Biology with a minor in English. She joined the Tsung-Zhang-Ruff Research Group in Fall 2024 and is currently completing her thesis in the lab on the role of the immune microenvironment in metabolic dysfunction-associated steatohepatitis. She is interested in pursuing a career in oncology.