Lieping Chen studies immune cell communications via cell surface protein-protein interactions. He is also interested in translating laboratory findings to treat human diseases including cancer, autoimmune diseases and infection.

In 1992, Dr. Chen showed the first proof-of-concept study that the B7-CD28 family molecules could be the targets for cancer immunotherapy. This study inspires subsequent studies targeting the B7-CD28 family molecules for the treatment of human cancer.

In 1999, Dr. Chen, then at the Mayo Clinic, first to discover a molecule he called B7-H1, which is now also known as PD-L1. He subsequently showed that PD-L1 is expressed by several types of tumors and that its activity can cause the death of T cells, thus preventing them from eliminating cancer cells. Bringing these lines of inquiry full circle, he later showed that blocking this interaction between PD-1 and PD-L1 by monoclonal antibodies improved the immune system’s ability to eliminate tumors in a 2002 paper. Chen’s work provided an important foundation for the subsequent development of immunotherapies designed to block this activity, and thereby enable more effective immune responses against cancer. Dr. Chen also initiated and help organized the first-in-man clinical trial of anti-PD-1 monoclonal antibody for treating human cancer in 2006, when he moved to the Johns Hopkins Medical Institute, and developed PD-L1 staining as a biomarker to predict treatment outcome. His discoveries directly led to the development of anti-PD-1/PD-L1 antibody therapy against broad spectrum of human cancers. These discoveries have revolutionized cancer treatment.