Lieping Chen

Lieping Chen, MD, PhD is the United Technologies Corporation Professor of Cancer Immunology and Co-Director of the Cancer Immunology Program at Yale Cancer Center, Yale School of Medicine. He is widely recognized as the discoverer of PD-L1 (which he originally termed B7-H1), the principal ligand for the PD-1 immune checkpoint. Working at the Mayo Clinic in 1999, Dr. Chen identified B7-H1 (now called PD-L1 or CD274) as a novel B7 family member that delivers co-inhibitory signals to T cells, and subsequently demonstrated in a landmark 2002 paper that B7-H1/PD-L1 is overexpressed on human cancer cells and suppresses tumor-specific T cell responses — directly explaining a major mechanism of cancer immune escape. This work provided a crucial molecular link between the PD-1 receptor and tumor immune evasion, and was instrumental in motivating the clinical development of anti-PD-L1 antibodies including atezolizumab, durvalumab, and avelumab. Dr. Chen's laboratory has also characterized multiple other B7 family members and their roles in immune regulation, and has been a leading voice in defining rational combination immunotherapy strategies. He is frequently cited among the most impactful scientists in the checkpoint immunotherapy revolution and has been involved in intellectual property proceedings regarding PD-L1 discovery priority. He has published more than 300 papers and has received numerous honors for his foundational contributions to cancer immunology.