Rochester, Minnesota


Yoon.Harry@mayo.edu Clinical Profile


The research focus of Harry H. Yoon, M.D., is in the development of novel therapies and the identification of biomarkers in esophagogastric and colorectal malignancies. He has expertise in cancers of the digestive system, as well as cancers of unknown primary and Merkel cell carcinoma.

Focus areas

  • Harnessing the immune system to fight cancer. Dr. Yoon is developing and has opened clinical trials studying agents that are intended to unleash the immune system's natural ability to eradicate tumors. He is also leading efforts to identify biomarkers that predict which patients are most likely to benefit from immune-modulating therapies.
  • Human epidermal growth factor receptors (HER2 and HER3). Dr. Yoon led the development of the largest clinically annotated, tissue-based cohort of esophageal and gastroesophageal junction (GEJ) adenocarcinomas in the world. Among their findings, the team discovered that tumors with HER2 genetic heterogeneity display particularly aggressive behavior.
  • Ramucirumab, an angiogenesis inhibitor. Dr. Yoon led an investigator-initiated national randomized phase II trial examining the effects of ramucirumab in people with previously untreated, advanced esophagogastric adenocarcinoma. Ramucirumab is a monoclonal therapeutic antibody targeting vascular endothelial growth factor receptor 2 (VEGFR-2), which has been shown to help people with previously treated gastric cancer live longer. In addition, Dr. Yoon is principal investigator of ongoing multiple studies to identify tissue, genetic and plasma-based biomarkers that predict ramucirumab benefit.

Significance to patient care

Dr. Yoon's research is intended to find cures for cancer particularly by harnessing the body's natural immune system. In addition, his work is intended to help clinicians do a better job of matching the right therapy with the right patient, to maximize the therapy's ability to fight the cancer while minimizing side effects. His approach to accomplishing this goal is through improving our understanding of the molecular characteristics of tumors so that novel agents and approaches can be tailored to the patient's tumor and host profile.

Professional highlights

  • Co-Chair, Esophageal/Gastric Cancer Disease Group, Mayo Clinic Comprehensive Cancer Center, 2017-present
  • Member, National Cancer Institute Esophagogastric Task Force, 2016-present
  • Panel member, National Comprehensive Cancer Network (NCCN), guidelines for cancer of unknown primary, 2016-present
  • Recipient, Charles F. and Marcia L. Forcey Career Development Award in Esophageal Cancer Research, 2011-2013
  • Recipient, Paul Calabresi Scholar (Mayo Clinic Comprehensive Cancer Center K12), 2008-2010
  • Recipient, Young Investigator Award, American Society of Clinical Oncology, 2007


Primary Appointment

  1. Consultant, Division of Medical Oncology, Department of Oncology

Academic Rank

  1. Professor of Oncology


  1. Clinical Post Doctoral Fellowship - Medical Oncology The Johns Hopkins University School of Medicine
  2. MHS Graduate Training Program in Clinical Investigation (GTPCI), Johns Hopkins School of Public Health
  3. Internship/Residency - Internal Medicine Traditional Program, Yale-New Haven Hospital, Yale University School of Medicine
  4. MD Yale University School of Medicine
  5. BS - Molecular Biophysics & Biochemistry Yale College

Mayo Clinic Footer