Deborah B. Doroshow

Deborah B. Doroshow, MD, PhD is Assistant Professor of Medicine in the Division of Hematology and Medical Oncology and Director of Clinical Science of the Early Phase Trials Unit at the Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai. Dr. Doroshow is a physician-scientist specializing in the development and clinical validation of translational biomarkers for cancer immunotherapy, with particular expertise in PD-L1 immunohistochemistry, tumor mutational burden (TMB), microsatellite instability (MSI), and composite immunophenotypic signatures as predictors of checkpoint inhibitor response. She completed her MD-PhD at Yale School of Medicine (laboratory of Dr. Patricia LoRusso and translational immunology) and fellowship training in experimental therapeutics and medical oncology at Weill Cornell/MSK, bringing a rigorous scientific training in immune biomarker biology to clinical drug development. Dr. Doroshow has led and contributed to multiple phase I and phase I/II trials of immune checkpoint inhibitors, novel immune combinations, and immunotherapy-targeted therapy combinations, always with a systematic translational biomarker co-development plan. Her landmark work on PD-L1 IHC assay harmonization — comparing four FDA-approved PD-L1 companion diagnostic assays (22C3, 28-8, SP142, SP263) across tumor types — has been cited thousands of times and directly influenced regulatory policy on PD-L1 testing standards. She actively contributes to the Blueprint PD-L1 harmonization initiative and is a recognized authority on the complexity of PD-L1 as a biomarker across immune and tumor cell compartments.