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Sandra M. Swain, MD, FACP, FASCO

Georgetown University Medical Center
Washington, D.C.

Titles and Affiliations

Professor of Medicine
Associate Dean of Research Development
Vice-President of Genetic Medicine

Research area

Developing strategies to improve treatment outcomes for HER2-positive breast cancer patients.


Human epidermal growth factor receptor 2 (HER2) is a protein found on the surface of all breast cells. When overexpressed, HER2 causes breast cells to grow rapidly—this occurs in approximately 20 percent of breast cancers which are called HER2-positive. These breast cancers tend to be more aggressive, however, they can also be effectively treated with HER2-targeted therapies. Dr. Swain has been focused on improving HER2-targeted therapies and her current work focuses on immune cells in the HER2-positive breast tumor microenvironment and the role they play in how the tumor responds to treatment. This will help inform treatment decisions and potentially improve treatment outcomes for these patients.

Progress Thus Far

Studies of the immune microenvironment have shown that one type of immune cell, called tumor infiltrating lymphocytes (TILs), can move from the blood into the tumor microenvironment where they can recognize and kill cancer cells. Specifically, the presence of TILs has been associated with better outcomes from HER2-targeted therapy. Based on these observations, Dr. Swain conducted a pilot study of primary and metastatic HER2-positive breast cancers to determine if immune cells play a role in the progression to metastases. They found that primary samples had a higher infiltration of immune cells, CD3 and CD45, and higher expression of immune activation and checkpoint markers when compared with metastatic samples. Interestingly, brain metastases had the lowest numbers of immune cells compared to other metastatic sites. These findings are in agreement with other studies showing that metastatic tumors are less immunogenic than primary tumors and could explain the limited efficacy of immune checkpoint inhibitors in treating these patients.

What’s next

Dr. Swain and her colleagues will leverage patient samples from multiple clinical trials to expand the study in a large clinical cohort. Collation of this data will be used to develop a prediction model based on characteristics of TILs, their presence across various patient populations, and gene expression patterns. Ultimately, this research could determine the utility of TILs and other immune cells as biomarkers to predict treatment outcomes and provide clinicians with a potentially important decision-making tool.


Dr. Sandra M. Swain is an internationally-recognized breast cancer medical oncologist, and clinical translational researcher. She has authored nearly 300 articles in numerous peer-reviewed medical journals, such as the New England Journal of MedicineLancet Oncology, and the Journal of Clinical Oncology, on topics including inflammatory breast cancer, adjuvant treatment of breast cancer, the treatments of metastatic HER2-positive breast cancer, cardiotoxicity, and health care disparities.

Throughout her career, Swain has held many advisory and leadership positions with professional oncology societies and organizations across the globe. From 2012 through 2013, she served as President of the American Society of Clinical Oncology where she championed efforts to promote the advancement of women in medicine and that she continues today through her service on the board of Conquer Cancer, the ASCO foundation, and the Women Who Conquer Cancer initiative she established. Currently, she is a professor at the Georgetown University School of Medicine, the Associate Dean for Research Development at Georgetown University Medical Center, and the Vice President of MedStar Genetic Medicine–roles in which she works to improve patients’ access to cutting-edge treatments and technologies by expanding medical research opportunities across the MedStar Health system. She is also co-chair of the Early Breast Cancer Trialists’ Collaborative Group in Oxford and a visiting professor of clinical oncology at the University of Oxford, UK.

BCRF Investigator Since


Areas of Focus

Survivorship Treatment