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Leslie L. Montgomery, MD, FACS

Chief, Division of Breast Surgery, Hackensack University Medical Center
Co-Chief, Breast Service, John Theurer Cancer Center
Hackensack University Medical Center
Hackensack, New Jersey

Current Research

Goal: To personalize therapies that are curative even for the most challenging cases of triple negative breast cancer (TNBC).

Impact: Drs. Montgomery and Feinman are studying the composition of gut and tumor bacteria and the role it plays in how the immune system recognizes and responds to tumors. Understanding the role that certain bacteria play in outcomes in TNBC patients may lead to new strategies to improve both the quality and duration of treatment by altering the levels of these bacteria.

What’s next: The team continues to enroll patients newly diagnosed with TNBC and will conduct analyses of gut and tumor bacteria to establish correlations with immune response and outcome.

One of the most important recent discoveries in cancer research is that the composition of gut and tumor bacteria plays a critical role in how the immune system recognizes tumors and responds to them. Triple negative breast cancer (TNBC) is an aggressive disease treated primarily by chemotherapy, but many patients don’t respond to it. Drs. Montgomery and Feinman are correlating changes in the composition of the gut and intratumoral microbiome with anti-tumor immune response in newly diagnosed TNBC patients before, during, and after chemotherapy. Their work may identify markers that predict poor outcome, which could lead to the development of personalized microbial-based therapies to enhance treatment responses in TNBC patients.

Full Research Summary

Research area: Identifying innovative approaches to improve response to therapies for triple negative breast cancer (TNBC), an aggressive form of the disease.

Impact: While significant progress has been made in the understanding of TNBC, there are still no targeted therapies available to treat it. Neoadjuvant (pre-surgical) chemotherapy can improve clinical outcomes, but only 30 percent of patients with TNBC respond to neoadjuvant chemotherapy. The work by Drs. Montgomery and Feinman could lead to biomarkers of response and interventions to improve response in patients with aggressive disease.

One of the critical goals is to identify predictors of response to neoadjuvant chemotherapy so that TNBC patients destined to do poorly can be identified earlier. The discovery that differences in the makeup of the gut and tumor microbiome, which consist of tens of trillions bacteria, can influence whether or not a patient responds to chemotherapy prompted Drs. Montgomery and Feinman to ask if certain types of gut and tumor bacteria increase the efficacy of neoadjuvant chemotherapy by re-activating the patient’s immune system. They aim to identify novel microbiota-associated biomarkers that predict poor outcome and could lead to the development of personalized microbial-based therapies to harness immunotherapeutic responses in treatment-refractory TNBC.

Current research: The team is conducting a prospective study in which they will correlate changes in the composition of the gut microbiome with anti-tumor immune response in newly diagnosed TNBC patients before, during, and after standard neoadjuvant chemotherapy. 

What they’ve learned so far: Drs. Montgomery and Feinman have found the presence of gram-positive and gram-negative bacteria in tumor biopsies of several TNBC patients prior to and after treatment with standard of care neoadjuvant chemotherapy.

What’s next: The team will add additional clinical sites to increase patient accrual for their study. They will use existing specimens from patients who were diagnosed with TNBC to determine if certain types of bacteria and gene expression profiles in patients’ tumors are associated with risk for residual disease and metastasis.


Dr. Leslie L. Montgomery is a board-certified surgical oncologist specializing in breast cancer. She is Chief of the Division of Breast Surgery at Hackensack University Medical Center and the Co-Director of the Breast Service at John Theurer Cancer Center. She was formally an attending breast surgeon at Memorial Sloan Kettering Cancer Center for more than 11 years, where she served as Director of the Special Surveillance Breast Program and the Director of the Breast Surgical Oncology Fellowship Program. From 2009 through 2015, Dr. Montgomery was the Chief of the Division of Breast Surgery at Montefiore Medical Center and the Director of Breast Services at the Montefiore Einstein Center for Cancer Care.

Dr. Montgomery received her undergraduate degree at Stanford University and earned her medical degree at the University of California,  San Francisco. After her residency in general surgery at the New York Hospital/Cornell Medical Center, she completed research fellowships at the Brigham and Women’s Hospital in Boston, Massachusetts and at Memorial Sloan Kettering Cancer Center.

Her research interests include preoperative therapy trials to reduce the burden of disease in the breast and axillary nodes to minimize surgical intervention.

Leslie L. Montgomery

BCRF Investigator Since


Donor Recognition

The Ann Taylor and Loft Award (a subsidiary of ascena retail group inc.)

Area(s) of Focus