He also serves as Director of Basic Science at the Basser Research Center for BRCA at the University of Pennsylvania. Dr. Greenberg’s research is focused on homology directed DNA repair and its relationship to cancer etiology and response to therapy. His laboratory has made important contributions to these areas by defining ubiquitin dependent recognition of DNA double-strand breaks, communication between DNA damage responses and transcription, mechanisms of alternative telomere length maintenance, and BRCA1 dependent DNA repair processes that contribute to the suppression of hereditary breast and ovarian cancer. This body of work has led to the identification of three cancer cancer susceptibility genes and the designation of biallelic mutation to the BRCA1 gene as a cause of a new Fanconi Anemia Subtype.