The physicians, nurses, technicians and administrative staff of Berkshire Hematology Oncology share a strong commitment to the care and comfort of our patients. We’re here for you every step of the way.

Dr. Michael DeLeo


Dr. DeLeo graduated magna cum laude from Harvard University, majoring in biology. He attended the University of Massachusetts Medical School and completed his residency program at Berkshire Medical Center. He had two fellowships: one in medical oncology at Vanderbilt University Medical Center in Nashville, Tennessee, the other in hematology at New England Deaconess Hospital in Boston. Dr. DeLeo is board certified in internal medicine, hematology and oncology.

Dr. Paul Rosenthal


After graduating magna cum laude from Muhlenberg University in Allentown, PA, Dr. Rosenthal attended Stanford University School of Medicine. He completed his medical internship at the Stanford Medical Center, and was a medical resident and hematology fellow at Peter Bent Brigham Hospital (now Brigham and Women’s Hospital). He completed his clinical and research fellowships in medicine at Harvard Medical School. Dr. Rosenthal is board certified in internal medicine, hematology and oncology.

Dr. Harvey Zimbler


A native of Chicago, Dr. Zimbler received a bachelor of science from the University of Michigan before attending medical school and completing a research fellowship at the University of Illinois. He completed both his internship and residency programs at Mt. Sinai Hospital in New York, NY, his cancer training at the National Cancer Institute in Bethesda, MD, and his hematology training at the National Institutes of Health in Bethesda, MD. Dr. Zimbler is a member of the Phi Beta Kappa Honorary Society and the Alpha Omega Alpha Honorary Society. He is board certified in oncology and hematology as well as internal medicine.

Sarah Bradford
Nurse Practitioner


Sarah Bradford has worked predominately in medical oncology for her entire nursing career. As an Oncology Certified Nurse (OCN), she has served as the nurse manager for Berkshire Hematology Oncology in addition to working extensively with patients. Board certified as an adult nurse practitioner, Sarah received a masters degree from Russell Sage College in Troy, New York. She holds a bachelor of science in nursing from the University of Massachusetts.