About Haley Ellis, MD

Dr. Ellis is a medical oncologist at Massachusetts General Hospital and Instructor in Medicine at Harvard Medical School. Her clinical practice involves caring for patients at the Tucker Gosnell Center for Gastrointestinal Cancers and the Henri & Belinda Termeer Center for Targeted Therapies, where innovative early phase clinical trials are conducted. 

As a research student in Dr. José Baselga’s laboratory at Memorial Sloan Kettering Cancer Center, Dr. Ellis delved into understanding resistance mechanisms to targeted therapies. Her work in this area led to publications in Nature and Cancer Cell and sparked her passion for pursuing a career as a physician-scientist. She earned her medical degree at University College Dublin in Ireland followed by internal medicine residency at Washington University in St. Louis. During her training, she garnered numerous accolades in medicine and oncology, including a competitive clinician-scientist research scholarship. Subsequently, Dr. Ellis completed a medical oncology fellowship at Dana-Farber Cancer Institute, Brigham and Women’s Hospital, and Massachusetts General Hospital, where she was selected as chief fellow. 

Dr. Ellis’ clinical and research interests are focused on biliary cancers (cholangiocarcinoma and gallbladder cancer). She is dedicated to advancing the understanding and treatments of these cancers by identifying new therapeutic targets and leading clinical trials. She is a member of the American Association for Cancer Research (AACR), American Society of Clinical Oncology (ASCO), European Society of Medical Oncology (ESMO), and International Cholangiocarcinoma Research Network (ICRN). Dr. Ellis enjoys collaborating with multidisciplinary clinical teams and patient advocates, including the Cholangiocarcinoma Foundation and CARE (Cholangiocarcinoma Awareness/Advocacy, Research, and Education) Team, to provide compassionate and comprehensive care to her patients.

Clinical Interests:



Mass General Cancer Center
55 Fruit St.
Boston, MA 02114
Phone: 617-724-4000

Medical Education

  • MD, University College Dublin
  • Residency, Washington University, Barnes-Jewish Hospital
  • Fellowship, Brigham and Women's Hospital
  • Fellowship, Dana Farber Cancer Institute
  • Fellowship, Mass General Hospital

American Board Certifications

  • Internal Medicine, American Board of Internal Medicine

Accepted Insurance Plans

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In addition to clinical care, Dr. Ellis is a translational researcher specializing in cholangiocarcinoma in Dr. Nabeel Bardeesy's laboratory at MGH. Since her fellowship training, she has actively contributed to patient-centered research, connecting clinical observations to scientific investigations through a bench-to-bedside and bedside-to-bench approach. In the lab, patient-derived models are used to understand the biology of cholangiocarcinoma, explore mechanisms of response and resistance to targeted therapies, and develop novel therapeutic strategies. Dr. Ellis has received a number of awards and grants supporting these research endeavors, including an ASCO Conquer Cancer Young Investigator Award. Her enthusiasm for clinical/translational research is driven by a deep commitment to improving outcomes for patients with cholangiocarcinoma.


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