Current Updates on PD-L1 and HER2 Testing in Gastroesophageal Cancer: A Practical Approach


Gastroesophageal cancers are commonly diagnosed at advanced stages, which portend poor prognoses and have limited available therapeutic options. Numerous clinical trials have recently begun to evaluate the prognostic implications of new biomarkers in this clinical setting, including PD-L1, HER2, and microsatellite instability-high (deficient mismatch repair). This lecture will touch on the clinical indications of these biomarkers, how to interpret the associated immunohistochemical tests, and how the respective treatments impact the prognosis of these cancers.

Originally published on April 6, 2023

Lecture Presenter

Katherine Boylan, MD

Katherine Boylan, MD

Assistant Professor of Pathology
University of Utah School of Medicine
Medical Director, Anatomic Pathology
ARUP Laboratories

Dr. Katherine Boylan is a medical director of anatomic pathology at ARUP Laboratories and an assistant professor at the University of Utah School of Medicine. Dr. Boylan received her medical degree from Charles E. Schmidt College of Medicine at Florida Atlantic University. She completed her residency in anatomic and clinical pathology at the University of Utah School of Medicine, and a fellowship in gastrointestinal and hepatobiliary pathology at the University of Chicago School of Medicine. Dr. Boylan is certified in anatomic and clinical pathology by the American Board of Pathology. She received an honorable mention award from the Rodger C. Haggitt Gastrointestinal Pathology Society for her Gastrointestinal Pathology – 2020 Abstract. Her research interests include sessile serrated polyps and the serrated colon cancer pathway, as well as pathology resident education.


After this presentation, participants will be able to:

  • Learn the indications for PD-L1 testing in gastroesophageal cancers
  • Understand the components within the Combined Positive Score (CPS) equation
  • Participate in practical examples for CPS scoring and identify common pitfalls
  • Identify the clinical utility for HER2 testing in gastroesophageal cancers
  • Learn the HER2 scoring system for gastroesophageal cancers and recognize the differences from the scoring system used in breast cancers

Sponsored by:

University of Utah School of Medicine, Department of Pathology, and ARUP Laboratories