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Lewis A. Chodosh, MD, PhD

Perelman Professor and Chair, Department of Cancer Biology
Abramson Family Cancer Research Institute
Perelman School of Medicine
University of Pennsylvania
Philadelphia, Pennsylvania

Current Research

Goal: To understand the mechanisms by which breast cancers develop and become resistant to therapy to identify potential prevention strategies.

Impact: Advances in cancer therapy have dramatically reduced the number of breast cancer deaths, but in spite of these successes, many patients will experience a recurrence. This may be due to residual cancer cells that persist following primary treatment for breast cancer. By studying the biology of tumor dormancy and recurrence, Dr. Chodosh hopes to identify therapeutic approaches that target residual cancer cells, thereby further reducing breast cancer mortality.

What’s next: He and his team will continue to investigate why breast cancer cells lie dormant for years and then re-emerge as recurrent tumors. He is particularly interested in how obesity, weight loss, and exercise influence the likelihood of tumor recurrence.

About 25 percent of patients treated for early-stage breast cancer will experience a breast cancer recurrence. There is a growing body of research that points to sleeping cancer cells – cells that have survived therapy and may lie dormant in the body until something wakes them – as the drivers of breast cancer recurrence. It’s unclear how these cells are able to survive in dormancy and what happens to cause them to re-emerge. Dr. Chodosh is conducting studies to understand these processes and believes obesity and weight loss may play a role.

Full Research Summary

Research area: Identifying the specific pathways and genes responsible for breast cancer recurrence and strategies for prevention.

Impact: Despite advances in the detection and treatment of breast cancer, up to 25 percent of patients will recur with metastatic disease over their lifetime. Recurrent breast cancers arise from the reservoir of residual cancer cells that survive and persist following primary treatment; however, it is not known how these cells are able to evade treatment and lie dormant in tissues for extended periods of time, eventually re-emerging to resume growth. Dr. Chodosh aims to unravel this mystery and identify the specific pathways and genes responsible for breast cancer recurrence—work that may provide critical new drug targets essential for the development of more effective therapies. 

Current investigation: He and his team are conducting studies to understand how and why obesity, weight loss, and exercise affect the risk of recurrence and death.

What he’s learned so far: Dr. Chodosh’s laboratory has made major strides towards understanding the reasons why breast cancers can recur and has dramatically advanced the ability to detect rare tumor cells that “hide” in the bone marrow of breast cancer patients.  

What’s next: He and his colleagues will continue to investigate tumor dormancy and recurrence in order to enable the design of behavioral and therapeutic interventions that could prevent tumors from recurring and therefore reduce the mortality associated with metastatic breast cancer.


Dr. Lewis A. Chodosh is a physician-scientist who received a BS in Molecular Biophysics and Biochemistry from Yale University, and MD from Harvard Medical School, and a PhD. in Biochemistry from M.I.T. in the laboratory of Dr. Phillip Sharp.  He performed his clinical training in Internal Medicine and Endocrinology at the Massachusetts General Hospital, after which he was a postdoctoral research fellow with Dr. Philip Leder at Harvard Medical School.  Dr. Chodosh joined the faculty of the University of Pennsylvania in 1994, where he is currently a Professor in the Departments of Cancer Biology, Cell & Developmental Biology, and Medicine.  Dr. Chodosh serves as Chairman of the Department of Cancer Biology, Associate Director for Basic Science of the Abramson Cancer Center, and Director of Tumor Biology for the Abramson Family Cancer Research Institute at the University of Pennsylvania.  Dr. Chodosh also serves as Editor-in-Chief of Breast Cancer.  His research focuses on genetic, genomic and molecular approaches to understanding breast cancer susceptibility and pathogenesis.

Grid Researcher Headshot - Chodosh L

BCRF Investigator Since


Donor Recognition

The Hamptons Paddle & Party for Pink Award