Mark B. Geyer, MD

Hematologic Oncologist

Conditions Treated

Memorial Sloan Kettering hematologic oncologist Mark Geyer
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About Me

I am a hematologist and medical oncologist who specializes in caring for people with leukemia. I am a member of the Leukemia Service and Center for Cell Engineering at Memorial Sloan Kettering. I am committed to providing personalized, compassionate care for our patients and their families.

I often meet patients and their families and caregivers during a very challenging and emotionally charged period in their lives. I value the strong partnerships I form with our patients and their caregivers through both illness and wellness. I want us to make important decisions about care together.

As a researcher, I want to improve the way we treat blood cancers. The past several years have seen exciting developments in therapies for acute lymphoblastic leukemia and chronic lymphocytic leukemia in particular. We have made strides in understanding these conditions. I hope to develop safe and effective therapies and to define how best to use them in caring for people with leukemia.

I have a strong interest in using the power of the immune system to fight blood cancers more effectively. This treatment approach is called immunotherapy. I am working to develop and deliver chimeric antigen receptor T cell therapies for people with leukemia or lymphoma. This field holds great promise, though it has a different set of challenges compared with traditional chemotherapy. Because of the skill and experience of the nurses and doctors at MSK, we are able to deliver the newest treatments in the safest possible manner.

When I meet with patients, my goal is for them to leave the appointment feeling informed and empowered. I want them to know that they are in good hands. I listen carefully to their perspective and address their concerns. I also explain the range of options available to us, outline the advantages and disadvantages of each, and offer my recommendation. I often remind my patients and their families that we never stop caring for them. Our entire team of experts will be there to support and guide them through all of the stages of their journey. 

  • Clinical Expertise: Adult Acute and Chronic Leukemias; Acute Lymphoblastic Leukemia (ALL); Chronic Lymphocytic Leukemia (CLL); Hairy Cell Leukemia; Lymphoproliferative Disorders; Cellular Immunotherapy
  • Awards and Honors: American Society of Hematology Scholar Award (2018-2020); Lymphoma Research Foundation Postdoctoral Fellowship Grant (2017-2019); Abstract Achievement Award, American Society of Hematology (2016); Conquer Cancer Foundation Merit Award, American Society of Clinical Oncology (2016)
  • Languages Spoken: English; Spanish
  • Education: MD, Columbia University College of Physicians and Surgeons
  • Residencies: Internal Medicine – Massachusetts General Hospital
  • Fellowships: Hematology/Medical Oncology – Memorial Sloan Kettering Cancer Center
  • Board Certifications: Internal Medicine; Hematology; Medical Oncology

See My Colleagues


Geyer MB, Hsu M, Devlin SM, Tallman MS, Douer D, Park JH. 2017. Overall survival among older U.S. adults with ALL remains low despite modest improvement since 1980: SEER analysis. Blood. 129: 1878-1881.

Park JH*, Geyer MB*, Brentjens RJ. 2016. CD19-targeted CAR T-cell therapeutics for hematologic malignancies: interpreting clinical outcomes to date. Blood. 127: 3312-3320.

Visit PubMed for a full listing of Mark B. Geyer’s journal articles

Pubmed is an online index of biomedical articles maintained by the U.S. National Library of Medicine and the National Institutes of Health.

Clinical Trials

Research is integral to our mission at Memorial Sloan Kettering, and clinical trials help us discover better forms of patient care and treatment. For you, this could mean access to a new therapy or therapy combination. Click to see a list of the trials I’m currently leading.


Most major health insurers offer plans that include MSK as one of their in-network providers. If MSK is in-network, it means all our doctors are too. Medicare and New York State Medicaid also provide benefits for care at MSK.

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