Dr. Leif Ellisen is Breast Cancer Program Director and a senior Investigator at the Massachusetts General Hospital (MGH) Cancer Center, and Professor of Medicine at Harvard Medical School. He is also co-Leader of the Breast Cancer Program at the Dana-Farber Harvard Cancer Center. He received his undergraduate degree from Harvard University, MD and PhD degrees from Stanford University, and completed residency training, oncology fellowship training, and postdoctoral research training at Brigham and Women’s Hospital, the Dana-Farber Cancer Institute, and MGH, respectively. The Ellisen laboratory’s research is focused on pathogenesis of breast and other cancers, with a particular focus on triple-negative breast cancer (TNBC), incorporating studies of tissue-specific development, transcription factor networks and DNA repair. Through a detailed molecular understanding of these factors we seek to improve diagnosis, therapeutic prediction, and treatment efficacy. Our published work within the last five years has revealed fundamental new genetic mechanisms in HR+ breast cancer (Reinbay et al, Nature 2017; Matissek et al, Cancer Discovery 2018) and discovered a new and therapeutically relevant signature of homologous recombination deficiency (Polak et al, Nat Genet 2017). Our work on a DNA damage response pathway led directly to a national clinical trial for triple-negative breast cancer (TNBC) at 10 major cancer centers (Isakoff et al, J Clin Oncol 2015), and to the discovery of a new oncogene controlling the tumor epigenome (Saladi et al, Cancer Cell 2017). We were among the first to define the intra-tumoral heterogeneity of TNBC (Karaayvaz et al, Nature Comm, 2018), and recently discovered that DNA damage and altered signaling precede histologic abnormalities in noncancerous breast tissues of BRCA2 mutation carriers (Karaayvaz et al, Science Advances, 2020).

The Ellisen lab is uniquely positioned to work at the interface of basic tumor biology and therapeutic application. The lab’s work is strongly supported by a network of collaborators and by the extensive research and clinical infrastructure of the MGH Cancer Center and Harvard Medical School.