Dr. Herbst on Targeting PD-1 and PD-L1 in Lung Cancer

Roy S. Herbst, MD, PhD, professor of Medicine at Yale Cancer Center and chief of Medical Oncology at Smilow Cancer Hospital at Yale-New Haven in Connecticut, discusses the differences of targeting PD-1 and PD-L1 when treating patients with lung cancer.

Herbst says a tumor is resistant to the immune system because PD-L1, a protein that is found on normal immune cells, is also found on the cancer cells. PD-L1 binds to PD-1, which is a receptor on the T cell.

If PD-1 is blocked, the interaction between PD-1 and PD-L1 is blocked on the T cell side, Herbst says. This causes the PD-1 to be unavailable to bind to PD-L2, a similar type of protein found on normal cells that regulates inflammation. Herbst says physicians are concerned that by blocking the PD-1 and PD-L2 interaction, there may be increased toxicity.