About Leif Ellisen, MD, PhD

Dr. Ellisen is Professor of Medicine at Harvard Medical School and Program Director for Breast Medical Oncology at the Mass General Cancer Center. He is also co-Leader of the Breast Cancer Program at the Dana-Farber/Harvard Cancer Center. He received his undergraduate degree from Harvard University, MD and PhD degrees from Stanford University, and completed residency training, oncology fellowship training, and postdoctoral research training at Brigham and Women's Hospital, the Dana-Farber Cancer Institute, and Mass General, respectively. Dr. Ellisen is widely published in the fields of cancer biology, treatment and genetics. As Director of Breast and Ovarian Cancer Genetics at Mass General, Dr. Ellisen's clinical practice is focused on cancer risk assessment, cancer prevention and early detection. Research in Dr. Ellisen's laboratory is in the vanguard of revolutionizing cancer treatment through personalized cancer therapies. Dr. Ellisen is best known for his work on triple-negative breast cancer (TNBC), one of the most aggressive forms of the disease.

Departments, Centers, & Programs:

Clinical Interests:




Massachusetts General Hospital
55 Fruit St.
Boston, MA 02114
Phone: 617-726-2000

Medical Education

  • PhD, Stanford School of Medicine
  • MD, Stanford University School of Medicine
  • Residency, Brigham and Women's Hospital
  • Fellowship, Dana Farber Cancer Institute
  • Fellowship, Massachusetts General Hospital

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In the Ellisen Laboratory, scientists identify genetic abnormalities in tumor cells that are not present in normal tissues, study how the abnormalities influence the biology of cancer cells, and explore how their new discoveries can inform the selection of the most effective therapy for each patient. Key tumor cell pathways under investigation in the laboratory include p53, BRCA1/2, and mTOR. Dr. Ellisen is best known for his work on triple-negative breast cancer (TNBC), one of the most aggressive forms of the disease. His research has shown that a chemotherapy drug used to treat several other types of cancer - but rarely breast cancer - holds promise for TNBC patients. Dr. Ellisen now oversees clinical trials of this and many other promising new therapies in breast cancer.


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