Photo of Leif William Ellisen, MD, PhD

Leif William Ellisen, MD, PhD

  • Program Director, Breast Medical Oncology
  • Professor of Medicine, Harvard Medical School
  • Clinical Director, Breast and Ovarian Cancer Genetics


Accepting New Patients


As Program Director for Breast Medical Oncology, Dr. Ellisen oversees an integrated and multidisciplinary unit focused on excellence in patient care and groundbreaking clinical and translational research.




Centers & Specialties

Cancer Center

Clinical Interests
  • Cancer genetics
  • Breast cancer
Medical Education
  • MD, PhD, Stanford University School of Medicine
  • Residency, Brigham and Women's Hospital
  • Fellowship, Dana Farber Cancer Institute
Board Certifications
  • Medical Oncology
Foreign Languages
  • French
  • Boston: Massachusetts General Hospital
Existing Patients
Patient Gateway
Insurances Accepted
  • Aetna Health Inc.
  • AllWays Health (NHP) - ACD
  • AllWays Health (NHP) - PBO
  • Beech Street
  • Blue Cross Blue Shield - Blue Care 65
  • Blue Cross Blue Shield - Indemnity
  • Blue Cross Blue Shield - Managed Care
  • Blue Cross Blue Shield - Partners Plus
  • BMC HealthNet Mass Health MCO/ACO
  • Cigna (PAL #'s)
  • Commonwealth Care Alliance
  • Fallon Community HealthCare
  • Great-West Healthcare (formally One Health Plan)
  • Harvard Pilgrim Health Plan - ACD
  • Harvard Pilgrim Health Plan - PBO
  • Health Care Value Management (HCVM)
  • Humana/Choice Care PPO
  • Maine Community Health Options (MCHO)
  • MassHealth
  • Medicare
  • Medicare - ACD
  • OSW - Maine
  • OSW - New Hampshire
  • OSW - Rhode Island
  • OSW - Vermont
  • Private Health Care Systems (PHCS)
  • Railroad Medicare
  • Railroad Medicare - ACD
  • Senior Whole Health
  • TriCare
  • Tufts Health Plan
  • Unicare
  • United Healthcare (non-HMO) - ACD
  • United Healthcare (non-HMO) - PBO
  • Well Sense Pediatrics

Note: This provider may accept more insurance plans than shown; please call the practice to find out if your plan is accepted.

Patient Age Group
Provider Gender


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.

Research & Publications

Research Summary

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.


View my most recent publications at PubMed

News & Events


  • Translational Research Lab (TRL)

    The Massachusetts General Hospital Cancer Center is committed to advancing oncology care by tailoring treatment options to the individual cancer patient. The basic mission of the Translational Research Laboratory (TRL) is to provide rapid personalized genomic testing as an important component of routine care, thereby minimizing generalizations made in treatment decisions.


Massachusetts General Hospital
55 Fruit Street
Boston, MA 02114-2696
Phone: 617-726-6500
Fax: 617-724-1079

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