Clinical Faculty

Dr. Fletcher is an Associate Professor of Medicine within the Division of Hematology and Oncology. He is a Veterans Administration Advanced Career Development Awardee, American Heart Association Career Development Awardee and Florida Biomedical Research Program NIR Awardee.

Dr. Mandernach is an associate professor of medicine within the division of hematology and oncology, and serves as a clinician educator with a focus on thrombosis and hemostasis and sickle cell disease. She is a member of the American Society of Hematology.

Carol Mathew, MD, is an assistant professor in the hematology/oncology division at the University of Florida Department of Medicine. She completed her undergraduate years at College of New Rochelle in New York, getting a Bachelor’s degree in Biology/Chemistry. She attended Ross University School of Medicine and graduated with her doctorate receiving the highest honors in 2013. Her post-doctoral training includes an internship and residency at the University of Massachusetts Medical School, and a fellowship in the division of hematology and oncology.

Mathew has received over six awards such as the President’s Award in the College of New Rochelle, New York, and Honor’s list for eight consecutive semesters. She currently serves on educational and administrative committees as well as clinical teaching activities. Mathew has presented her research at a local, state and national level specializing in leukemia and cardiac risk factors. Additionally, she has contributed to peer-reviewed and non-peer-reviewed publications analyzing multidisciplinary approaches to caring for geriatric patients with cancer.

Dr. Rajasekhar is a clinician and clinical investigator with a focus on benign hematology, specifically thrombosis and hemostasis. She is a member of the American Society of Hematology and the Hemostasis and Thrombosis Research Society.

Dr. Zumberg is recognized as an outstanding clinician-educator in the Division of Hematology/Oncology and the Department of Medicine.   He serves as Section Chief for benign hematology and holds various medical directorships.  He is chairman of the Shands Hospital Transfusion Committee.  He is noted as a key clinical faculty member in the Internal Medicine residency training program and the Division of Hematology/Oncology Fellowship Program.

Karen C. Daily, DO, is an associate professor of medicine in the Division of Hematology and Oncology at the University of Florida College of Medicine.

Dr. Daily earned her Bachelor of Science from The Ohio State University and her medical degree from Lake Erie College of Osteopathic Medicine. She completed residency at Wyckoff Heights Medical Center in internal medicine and fellowship at UF in hematology and oncology. She served three years active duty in the United States Army.

Dr. Daily is a clinically-based investigator and educator with a focus in breast cancer. She is board-certified in internal medicine, medical oncology, and hematology. She is a member of the American Society of Clinical Oncology and Co-Chair of the Epidemiology and Prevention Item Writing Task Force. Dr. Daily serves as the Division Education Director and is the recipient of multiple teaching awards including the Fellowship Positive Impact Award.

Dr. Daily founded the High Risk Program, within UF Health Breast Center, that identifies women at above-average risk of developing breast cancer and offers prevention and early detection strategies. Dr. Daily serves as Associate Medical Director of the Medical Oncology Clinic. She is committed to resolving access to care barriers in disadvantaged populations and passionate about improving the efficiency of the health care system.

Through her role as the Breast Cancer Disease Site Group’s Research Leader, Dr. Daily is dedicated to increasing available clinical trials, both large cooperative group studies and early phase single institution investigations, so that every patient may be offered the opportunity to participate. She is an active member of the National Surgical Adjuvant Bowel and Breast Project (NSABP)/NRG Oncology and has served as Co-Chair of the Rare Breast Cancer Committee.

Dr. Heldermon is an associate professor of medicine, board certified medical oncologist with expertise in the treatment of breast cancer. He is a member of the American Society of Hematology and the American Society of Clinical Oncology. His research expertise is in the use of gene replacement and stem cell therapies for the treatment of inherited disorders such as lysosomal storage diseases. He also studies the spread of stem cells from maternal or malignant sources using mouse models.

Dr. Staal’s professional career spans more than 35 years and includes conducting basic and applied cancer research, caring for patients, and organizing and administering a clinical cancer program. He has an interest in the molecular mechanisms that define cancer cells and how these can be exploited therapeutically. Clinically his interests are focused on experimental therapeutics, breast cancer, and clinical management to promote research and improve patient care.

Dr. George is a clinical investigator and educator with a focus on gastrointestinal malignancies. As director of the GI Oncology Program at the University of Florida, Dr. George helps to oversee the treatment of all patients with GI malignancies. He previously served as chair of the Medical Advisory Board to the State of Florida Department of Health and the Screen for Life Colorectal Cancer Screening Program, which targets historically underserved populations. He also recently completed a 10 year term as the gubernatorial-appointed chair of the Florida Cancer Control and Research Advisory Council, which advises the legislature, Department of Health, and state surgeon general on all cancer related matters and policy. He currently serves as the Associate Director for Clinical Research at the UF Health Cancer Center. Through participation with large oncology clinical trial cooperative groups and the National Cancer Institute, Dr. George is an active clinician and clinical investigator in GI malignancies and early phase clinical trials testing new therapies for patients with advanced cancers. He is a member of the medical honor society Alpha Omega Alpha, the American Society of Clinical Oncology, and numerous cancer research groups.

Sherise C. Rogers, M.D., M.P.H., received her bachelor’s degree from Cornell University in 2009 in Human Development with a minor in Biological Sciences. She then obtained her Medical Doctorate in 2014 and Master in Public Health in 2015 from New York Medical College.

Dr. Rogers completed her Internal Medicine Residency at Stony Brook University Medical Center in New York in 2017. She completed her Hematology & Oncology Fellowship at The Ohio State University Medical Center where she also served as Wellness Chief Fellow in 2020. Aside from her educational achievements, Dr. Rogers has a passion for mentoring and has completed many professional development programs such as the Physician Leadership Academy and Medical Journalism elective at the ABC News Medical Unit in New York City.

Her peer reviewed publications and presentations have concentrations in gastrointestinal oncology, diversity and inclusion, physician wellness and strategies to address burnout among hematology and oncology trainees. She is a member of many professional memberships such as the ASCO and AACR.

Dr. Rogers’ area of clinical and research focus are gastrointestinal malignancies with a special interest in pancreatic cancer, the microbiome, circulating tumor DNA and cancer disparities.

Brian Ramnaraign, MD is an assistant professor of medicine in the division of hematology and oncology at the University of Florida College of Medicine.

Dr. Ramnaraign attended the University of Toronto for his undergraduate studies where he was awarded an Honors Bachelors of Science degree with a specialization in molecular genetics and microbiology. This was followed by attending St. George’s University for his medical training where he was awarded the degree of Doctor of Medicine and graduated cum laude.

His internal medicine residency was completed at SUNY Downstate in Brooklyn, NY where Dr. Ramnaraign had the opportunity to participate in rotations at Memorial Sloan Kettering in Manhattan. After residency he obtained a fellowship in geriatrics at the University of Pennsylvania in Philadelphia, PA.

Dr. Ramnaraign completed his hematology and oncology fellowship here at the University of Florida and upon completion stayed on as faculty. His wife is also here at the University of Florida and is training to be a pediatric oncologist.

His expertise and research interests are in the fields of genitourinary cancers, gastrointestinal cancers and neuroendocrine cancers. He is interested in the role of targeted therapies and immunotherapies in providing personalized treatments to individuals with advanced cancers.​

Ilyas Sahin, MD, is an assistant professor with the division of hematology & oncology. At UF Health, he specializes in gastrointestinal oncology.

Dr. Sahin earned his medical degree from Hacettepe University Faculty of Medicine in Turkey. He then worked as postdoctoral research fellow in medical oncology at Dana-Farber Cancer Institute, Harvard Medical School.

He completed his internship at Montefiore Medical Center, Albert Einstein College of Medicine and a residency at Mount Auburn Hospital, Harvard Medical School, both in internal medicine. Most recently he completed a fellowship at Rhode Island Hospital, Brown University in hematology and oncology.

Before joining UF Health, Dr. Sahin was an assistant professor of medicine at The Warren Alpert Medical School, and a clinical hematologist/oncologist at Miriam Hospital with the Lifespan Cancer Institute.

Dr. Sahin’s research interests gave led to more than thirty research papers and abstracts. In addition to focusing on his own research which primarily focuses on cancer immunotherapy and immunotherapy resistance, he currently serves as Associate Editor for Frontiers in Oncology. His work on the role of MDM2 in immunotherapy resistance was published with multiple online news networks and it was among CDDpress journals monthly readers’ choice. Recently, he developed a novel preclinical animal model for hyperprogression, acceleration of cancer growth (more rapid than expected), which occurs in some of cancer patients receiving immunotherapy. This novel model may help understanding unusual patterns of response and/ or resistance to immunotherapies which may provide key knowledge to develop new therapies in cancer patients.

Dr. Sahin is board certified in Internal Medicine, Hematology and Medical Oncology. He is also a member of the American Society of Clinical Oncology.

Dr Murillo has had multiple enriching experiences in other institutions prior to joining UF. She did her internship in Internal Medicine at St Vincent’s Hospital in Worcester, Massachusetts then went on to finish Internal Medicine residency at Johns Hopkins University/Sinai Hospital of Baltimore. She then went on to Montefiore Medical Center in New York, where she completed her fellowship in Hematology and Medical Oncology.

After completing fellowship, she moved to Ashland, Kentucky, where she started a hospital based private practice and was active in creating a more robust oncology program in that institution.

Dr. Staal’s professional career spans more than 35 years and includes conducting basic and applied cancer research, caring for patients, and organizing and administering a clinical cancer program. He has an interest in the molecular mechanisms that define cancer cells and how these can be exploited therapeutically. Clinically his interests are focused on experimental therapeutics, breast cancer, and clinical management to promote research and improve patient care.

Brian Ramnaraign, MD is an assistant professor of medicine in the division of hematology and oncology at the University of Florida College of Medicine.

Dr. Ramnaraign attended the University of Toronto for his undergraduate studies where he was awarded an Honors Bachelors of Science degree with a specialization in molecular genetics and microbiology. This was followed by attending St. George’s University for his medical training where he was awarded the degree of Doctor of Medicine and graduated cum laude.

His internal medicine residency was completed at SUNY Downstate in Brooklyn, NY where Dr. Ramnaraign had the opportunity to participate in rotations at Memorial Sloan Kettering in Manhattan. After residency he obtained a fellowship in geriatrics at the University of Pennsylvania in Philadelphia, PA.

Dr. Ramnaraign completed his hematology and oncology fellowship here at the University of Florida and upon completion stayed on as faculty. His wife is also here at the University of Florida and is training to be a pediatric oncologist.

His expertise and research interests are in the fields of genitourinary cancers, gastrointestinal cancers and neuroendocrine cancers. He is interested in the role of targeted therapies and immunotherapies in providing personalized treatments to individuals with advanced cancers.​

Jonathan Chatzkel, MD is an assistant professor of medicine in the division of hematology and oncology at the University of Florida College of Medicine. Dr. Chatzkel attended the University of Pennsylvania where he graduated magna cum laude, receiving a Bachelors of Arts degree with honors in Economics. He completed his medical degree at the Perelman School of Medicine at the University of Pennsylvania, followed by an internal medicine residency at Washington University in St. Louis, MO and a hematology and oncology fellowship at the Moffitt Cancer Center in Tampa, FL. Dr. Chatzel’s clinical interests include the care of patients with genitourinary cancers, including cancers of the kidney, bladder, prostate, and testis. He believes strongly in delivering individualized care to each of his patients. Professional affiliations include the American Society of Clinical Oncology, or ASCO.

Merry Jennifer Markham, MD, FACP, FASCO, professor of medicine, is chief of the division of hematology and oncology within the department of medicine and serves as the associate director for medical affairs at the UF Health Cancer Center. She is the research lead for the UFHCC’s Gynecologic Cancers Disease Site Group. She is the principal investigator for all chemotherapeutic and investigational therapy trials for gynecologic cancers and is site PI for all Gynecologic Oncology Group/NRG Oncology gynecologic cancer trials. Dr. Markham earned her medical degree at the University of Miami Miller School of Medicine and then completed her residency in internal medicine at UF where she served as chief medical resident and later completed a fellowship in hematology and oncology. Clinically, Dr. Markham’s primary focus is on the care of women with gynecologic malignancies. Her research is focused on investigations of experimental therapeutics and prognostic factors for gynecologic malignancies. Dr. Markham is also involved in the study of quality of cancer care, quality improvement strategies and cancer survivorship. Dr. Markham is board-certified in medical oncology. She is also a member of the American Society of Clinical Oncology, the American College of Physicians, the Society of Gynecologic Oncology and several clinical trial cooperative groups.

Martina Murphy, MD is an associate professor of medicine in the Division of Hematology and Oncology at the University of Florida. She is clinical investigator and medical educator with a passion for women’s health who specializes in caring for patients with gynecologic malignancies. Her research focuses in the equitable and accurate healthcare communication across the oncology spectrum. Dr. Murphy has a strong dedication to medical education and is actively involved on a national level in research in medical education primarily related to mentorship, career development and novel curriculum development. She serves as the Program Director for the UF Hematology/Oncology fellowship program. Additionally, she is the Course Director for Introduction to Clinical Medicine 1 & 2, part of an 18 month longitudinal clinical skills curriculum for pre-clerkship medical students.

Dr. Murphy is board certified in Internal Medicine, Hematology and Oncology and is a member of the American Society of Clinical Oncology (ASCO), is a graduate of the ASCO Educational Scholars Program and serves as the Vice-Chair for Mentorship in ASCO’s Medical Education Community of Practice. She is a graduate of the ASH Medical Educators Institute where she previously served as a faculty mentor. She sees patients with gynecological cancer at UF Health.

Karen C. Daily, DO, is an associate professor of medicine in the Division of Hematology and Oncology at the University of Florida College of Medicine.

Dr. Daily earned her Bachelor of Science from The Ohio State University and her medical degree from Lake Erie College of Osteopathic Medicine. She completed residency at Wyckoff Heights Medical Center in internal medicine and fellowship at UF in hematology and oncology. She served three years active duty in the United States Army.

Dr. Daily is a clinically-based investigator and educator with a focus in breast cancer. She is board-certified in internal medicine, medical oncology, and hematology. She is a member of the American Society of Clinical Oncology and Co-Chair of the Epidemiology and Prevention Item Writing Task Force. Dr. Daily serves as the Division Education Director and is the recipient of multiple teaching awards including the Fellowship Positive Impact Award.

Dr. Daily founded the High Risk Program, within UF Health Breast Center, that identifies women at above-average risk of developing breast cancer and offers prevention and early detection strategies. Dr. Daily serves as Associate Medical Director of the Medical Oncology Clinic. She is committed to resolving access to care barriers in disadvantaged populations and passionate about improving the efficiency of the health care system.

Through her role as the Breast Cancer Disease Site Group’s Research Leader, Dr. Daily is dedicated to increasing available clinical trials, both large cooperative group studies and early phase single institution investigations, so that every patient may be offered the opportunity to participate. She is an active member of the National Surgical Adjuvant Bowel and Breast Project (NSABP)/NRG Oncology and has served as Co-Chair of the Rare Breast Cancer Committee.

Dr. Kaye is a professor of medicine, medical director of the thoracic oncology program and director of the lung cancer center within the division of hematology and oncology. He is a clinical and basic science investigator with a focus on thoracic malignancies. Dr. Kay is an elected member of the American Society for Clinical Investigation, the Alpha Omega Alpha medical honor society, and serves as Associate Editor of the Journal of the National Cancer Institute.

Dr. Jones is a Professor with the Division of Hematology & Oncology at the University of Florida. He is a board certified medical oncologist with expertise in the study and treatment of lung cancer. He completed his undergraduate and medical degrees at Washington University in St. Louis, Missouri, then completed in residency in Internal Medicine at the Baylor College of Medicine in Houston, Texas, and then his fellowship in Oncology at the University of Texas MD Anderson cancer Center, where he remained on the faculty. After two years of research at Genentech, Inc., he returned to academic medicine at the University of Texas Medical Branch, and then joined the faculty of the University of New Mexico as the Director of Thoracic Oncology as well as the Medical Director of the New Mexico Cancer Care Alliance.

Dr. Lynch received his BA from the University of Virginia and MD from Eastern VA Medical School in 1984. After internal medicine training at the University of Florida, he did his training in medical oncology at the National Cancer Institute in Bethesda MD. In 1991 he returned to the UFCOM and has served in multiple roles during this tenure including, course director in Oncology (20 years), program director for hematology/oncology (13 years), section chief of hematology/oncology at the VAMC and now serves as the Assistant Dean for Admissions. He is a nationally recognized well published expert in the diagnosis and treatment of lymphomas and has coauthored over 130 papers, book chapters and abstracts. His educational roles include teaching cancer biology, clinical oncology, clinical reasoning and humanism in medicine. He was the first faculty inductee into the Chapman Humanism Society at the UFCOM and serves on its board of directors. He has received multiple teaching awards including clinical teacher of the year 5 times, the Hippocratic award three times, is a member of the College of Medicine Society of Teaching Scholars and in 2006 was honored by the University of Florida as one of 5 Distinguished Teaching Scholars. He was co-founder with his wife of the Christian Study Center at the University of Florida and serves as its board president. He and his wife Laura, have 4 children and 3 grandchildren.

Julia Close, MD is a professor of medicine in the Division of Hematology and Oncology at the University of Florida. Her primary appointment is as the Associate Dean of Graduate Medical Education and the Designated Institutional Official (DIO) for the University of Florida College of Medicine. She was previously the Program Director for the Hematology/Oncology Fellowship Program.  She is a clinician educator, with research interest in curriculum related to general oncology and interactions with patients at the end of life. She is actively nationally in education, serving on the American Society of Clinical Oncology (ASCO)’s Professional Development Committee and the In-Training Exam Writing Committees for both Internal Medicine and Oncology.  She was previously Section Chief of Oncology at the Gainesville VAMC, and was the Assistant Chief of the Medical Service from 2015-2018. She previously chaired the VHA Oncology Field Advisory (FAC) Committee, a national committee providing guidance for national VA policy. She is interested in performance improvement in oncology, and has a national role in this through the VA FAC and through her membership on ASCO’s Workforce Advisory Group Committee.

My name is Bently Doonan, MD, and I am an assistant professor in the University of Florida Division of Hematology & Oncology. I received both my Master of Biomedical Sciences, specialization in cancer immunology, and my medical degree from the Medical University of South Carolina in Charleston. Following medical school, I completed an internal medicine residency and a fellowship in hematology and oncology at UF. During my time at UF, I took on multiple leadership roles, including chief resident of internal medicine, curriculum development and quality and efficiency.

I am board certified in internal medicine and oncology by the American Board of Internal Medicine and an active member of multiple professional organizations, including the American College of Physicians, the American Society of Clinical Oncology, the Society for Immunotherapy of Cancer, the Society for Neuro-Oncology and the American Association for Cancer Research.

My clinical and research interests focus on melanoma, immunotherapy development and design, brain metastases and identification of microenvironment targets to induce an immunogenic response in advanced metastatic disease.

As a physician, my goal is to improve the lives of patients with advanced skin cancer and brain metastases through novel treatment approaches using immunotherapy to minimize toxicity and maximize potential benefits. I am also passionate about cancer research and actively design and develop clinical trials for patients with unmet needs in cancer.

During my free time, I enjoy spending time with my family and rooting on the Gators.

Dr. Staal’s professional career spans more than 35 years and includes conducting basic and applied cancer research, caring for patients, and organizing and administering a clinical cancer program. He has an interest in the molecular mechanisms that define cancer cells and how these can be exploited therapeutically. Clinically his interests are focused on experimental therapeutics, breast cancer, and clinical management to promote research and improve patient care.

Dr. Kaye is a professor of medicine, medical director of the thoracic oncology program and director of the lung cancer center within the division of hematology and oncology. He is a clinical and basic science investigator with a focus on thoracic malignancies. Dr. Kay is an elected member of the American Society for Clinical Investigation, the Alpha Omega Alpha medical honor society, and serves as Associate Editor of the Journal of the National Cancer Institute.

Dr. Jones is a Professor with the Division of Hematology & Oncology at the University of Florida. He is a board certified medical oncologist with expertise in the study and treatment of lung cancer. He completed his undergraduate and medical degrees at Washington University in St. Louis, Missouri, then completed in residency in Internal Medicine at the Baylor College of Medicine in Houston, Texas, and then his fellowship in Oncology at the University of Texas MD Anderson cancer Center, where he remained on the faculty. After two years of research at Genentech, Inc., he returned to academic medicine at the University of Texas Medical Branch, and then joined the faculty of the University of New Mexico as the Director of Thoracic Oncology as well as the Medical Director of the New Mexico Cancer Care Alliance.