Dr. Factor on the Lack of Standardization in Biomarker Testing in Breast and GI Cancers

Rachel E. Factor, MD, MS, associate professor of pathology, Pathology, Clinical Science Departments, Duke University, discusses the lack of standardization with biomarker testing in breast and gastrointestinal (GI) cancers.

Biomarker testing began in breast cancer with the evaluation of HER2, estrogen receptor, and progesterone receptor status, Factor says. Subsequently, biomarker testing emerged in GI cancers, as well as lung cancer, with the goal of offering targeted therapies to patients. However, biomarker testing remains a moving target that will continue to evolve as more clinical trials are completed, Factor explains.

Although HER2 is a biomarker of interest in both breast and GI cancers, pathologists interpret the results of the tests differently, Factor says. Moreover, the ASCO/CAP guidelines for testing are inconclusive and are based on multiple clinical trials that utilized different testing methods for HER2. With this lack of standardization, it is important to have conversations with other pathologists to understand best practices with biomarker testing, Factor concludes.