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Michael F. Press, MD, PhD

University of Southern California
Los Angeles, California

Titles and Affiliations

Professor of Pathology
Harold E. Lee Chair in Cancer Research
Director of Breast Cancer Analysis Lab
Keck School of Medicine

Research area

Refining breast cancer biomarkers for predicting response to targeted therapies in order to improve personalized medicine.


Breast cancer molecular markers, such as HER2, estrogen receptor, and progesterone receptor, are used in a clinical setting to select treatments for patients. Because they act as major drivers of breast cancer, they have been successful therapeutic targets. Dr. Press and his team are working to improve treatment response using known biomarkers and to identify new breast cancer biomarkers to help guide treatment decisions and reduce drug resistance. This work may improve patient selection for existing therapies and identify new targets for therapy.

Progress Thus Far

The team is involved in several research projects that could impact personalized medicine for breast cancer patients. Dr. Press is studying HER2 gene amplification status, which leads to more HER2 molecules on the cell surface than normal (HER2-positive), as well as steroid hormone receptor status. He and his team are investigating associations of these molecular alterations with responsiveness to various treatments as measured by clinical outcomes. Dr. Press’ laboratory serves as the center for several breast cancer clinical trials of novel therapies, including a trial of an antibody-drug conjugate called trastuzumab-deruxtecan (T-Dxd; ENHERTU), in patients whose breast cancers are considered HER2-low. HER2-low breast cancers have low to moderate levels of HER2 on the cell surface and were previously not treated with HER2-targeted therapies. Treating breast cancers that have low levels of HER2 opens a new therapeutic option to many patients, including some whose breast cancer had been classified as triple-negative (TNBC), for which there are limited treatment options. Dr. Press also continued long-standing collaborative studies to identify breast cancer risk elements in the genome, especially in women of African ancestry

What’s next

In the coming year, Dr. Press will continue his work developing and evaluating biomarkers used to define HER2-positive breast cancer to better understand how this molecular driver might vary between tumors. The team will continue refining the diagnostic testing issues that define the lower limits of HER2 to bring HER2-low therapy to more patients.


Dr. Press is a Professor in the Department of Pathology and holds the Harold E. Lee Chair in Cancer Research at the University of Southern California’s Norris Comprehensive Cancer Center. Dr. Press is a board certified pathologist, directs the USC Breast Cancer Analysis Laboratory as well as the Central Laboratory for the Translational Research In Oncology (TRIO)/Cancer International Research Group (CIRG), and is Leader of the USC Clinical Laboratories.

His laboratory evaluates prognostic and predictive markers used in making treatment decisions for women with breast cancer. It has served as the Central Laboratory for either retrospective or prospective analyses of tissue specimens for 18 clinical trials that collectively accrued more than 13,000 patients. Dr. Press’s area of research interest is in molecular alterations of breast and gynecologic cancers, especially those that have the potential to be important in either diagnostic or therapeutic decision-making for patient management. His research has been continuously funded by research grants for more than 25 years. He is the author or co-author of more than 200 peer-reviewed publications. The most prominent area of activity for his laboratory has been in the study of the human epidermal growth factor receptor type 2 (HER2) in breast and other cancers. He published his first paper in this area in 1989 (Science 244: 707-712) and his laboratory is still actively contributing to this area as well as to the conduct of clinical trials evaluating HER2 as a target for therapy.

BCRF Investigator Since


Donor Recognition

The Women's Cancer Research Fund Award

Areas of Focus

Treatment Tumor Biology