CD274 and cancer: As an example, expression of PD-L1 showed a significant association with response to durvalumab (an anti-PD-L1 antibody) in recent studies of head and neck cancer (5, 29).These studies found that a cutoff of 25% of cancer cells staining with PD-L1 is suitable to determine the patient ́s response to durvalumab immunotherapy (5, 29).