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Michael F. Press, MD, PhD

Professor of Pathology
Harold E. Lee Chair in Cancer Research
Director of Breast Cancer Analysis Lab
Keck School of Medicine
University of Southern California
Los Angeles, California

Current Research

  • Seeking biomarkers that can predict response to targeted therapies so that more personalized treatment strategies can be employed.
  • Laboratory studies are ongoing to identify molecular markers that could be used to select breast cancer patients for various targeted therapies.
  • This research will help to match patients to the right drugs for their tumor.

Targeted therapies have dramatically improved outcomes for patients with estrogen or HER2-driven breast cancers (called estrogen receptor- or HER2-positive breast cancer, respectively). Even after initial response, however, these cancers can develop resistance to the therapy and continue to grow. Dr. Press is conducting studies to identify changes in genes that drive drug resistance for the development of more personalized therapies. 

Full Research Summary

Predictive markers, such as estrogen receptor (ER) and HER2, play an important role in selecting the most appropriate (targeted) treatment for women with breast cancer. Resistance to therapies targeting ER or HER2 remains a clinical challenge, as effective therapies are limited for patients whose cancers have progressed on these therapies. 

Dr. Press and his team are conducting a series of laboratory studies to identify and characterize new molecular markers of resistance to both anti-HER2 and anti-estrogen treatment. Two genes of interest are called MYST2 and PIK3CA, both of which are suspected of playing a role in drug resistance. 

Dr. Press' team previously identified changes in the HER2 and MYST2 genes as well as upregulation of PIK3CA and the estrogen receptor in drug resistant cancer. In the coming year, they will work to correlate these alterations with treatment outcomes in breast cancer patients. They are also assessing whether mutations in genes that work with the estrogen receptor—called co-regulators—play a role in anti-estrogen resistance.

These studies are expected to have both an immediate and potentially long-term impact on personalized medicine for breast cancer 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, 1989) 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.

Grid Researcher Headshot - Press M

BCRF Investigator Since


Donor Recognition

The Bloomingdale's Award

Area(s) of Focus