Rochester, Minnesota


Yoon.Harry@mayo.edu Clinical Profile


The research focus of Harry H. Yoon, M.D., is in the development of biomarkers and therapies for esophagogastric and colorectal malignancies. Dr. Yoon has expertise in cancers of the digestive system, as well as cancers that spread from an unknown location — cancer of unknown primary — and Merkel cell carcinoma.

Focus areas

  • Human epidermal growth factor receptors 2 and 3 (HER2 and HER3). Dr. Yoon developed the largest clinically annotated, tissue-based cohort of esophageal and gastroesophageal junction (GEJ) adenocarcinomas in the world. Using this unique resource, Dr. Yoon's team found that the clinical impact of the HER2/ERBB2 gene aberrations differ based on the presence of premalignant lesions and that tumors with HER2 genetic heterogeneity display particularly aggressive behavior. His team determined that HER3/ERBB3, a potential therapeutic target that partners with HER2, is frequently overexpressed in esophageal and GEJ tumors and tends to be coexpressed with HER2. This supports the concept of dual targeting of HER2 and HER3.
  • Ramucirumab — an angiogenesis inhibitor. Dr. Yoon is the principal investigator of a U.S.-based 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. In addition, Dr. Yoon is principal investigator of multiple studies to identify tissue, genetic and plasma-based biomarkers that predict ramucirumab benefit.
  • 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.

Significance to patient care

Dr. Yoon's research is intended to help clinicians do a better job of matching the right therapy with the right patient, so as to maximize the therapy's ability to fight the cancer while minimizing side effects. Dr. Yoon's approach to accomplishing this goal is through improving 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

  • Recipient, Young Investigator Award, American Society of Clinical Oncology
  • Recipient, Charles F. and Marcia L. Forcey Career Development Award in Esophageal Cancer Research
  • Scholar, Paul Calabresi Training Program in Clinical-Translational Research, Mayo Clinic Cancer Center K12
  • Panel member, National Comprehensive Cancer Network, Guidelines for Cancer of Unknown Primary
  • Former junior member, National Cancer Institute Esophagogastric Task Force


See my publications


Academic Rank

  1. Assistant 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

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