John O Mascarenhas

John O Mascarenhas, MD

  • PROFESSOR | Medicine, Hematology and Medical Oncology


Hematology-Oncology, Cancer (Oncology)


Dr. John Mascarenhas is Professor of Medicine at the Icahn School of Medicine at Mount Sinai, Director of the Center of Excellence for Blood Cancers and Myeloid Disorders, and a member of The Tisch Cancer Institute. He directs the Adult Leukemia Program and leads clinical investigation within the Myeloproliferative Disorders Program. As a clinical investigator in malignant hematology with a focus on translational research involving myeloproliferative neoplasms (MPNs) and evolution to acute myeloid leukemia (AML), Dr. Mascarenhas evaluates rationale-based novel therapies for patients with MPNs and AML.

Dr. Mascarenhas is Principal Investigator (PI) of the clinical trials project within the National Cancer Institute-sponsored Myeloproliferative Neoplasms Research Consortium. He has served as PI or Study Chair of multiple investigator-initiated and industry-sponsored early- and late-phase clinical trials evaluating innovative approaches to the treatment of MPNs and AML. Additionally, he holds multiple administrative roles at Mount Sinai—he is Chair of the Leukemia Disease Management Team, Co-Chair of the Hematologic Malignancy Disease Focus Group, and a full member of the Tisch Cancer Institute Protocol and Review Monitoring Committee.



Clinical Focus

  • Chronic Myelocytic Leukemia
  • Eosinophilia
  • Myelodysplastic Syndromes
  • Primary Polycythemia


MD, New York Medical College

Residency, Internal Medicine, Rhode Island Hospital

Fellowship, Hematology, The Mount Sinai Hospital

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