In some nivolumab studies, PD-L1 expression was evaluated using anti-PD-L1 monoclonal antibody 5H1 (threshold for positivity: 5% expression per specimen), whereas others used an automated IHC assay based on a sensitive and specific anti-PD-L1 monoclonal antibody, 28-8 (positivity: ≥5% tumor cells showing membrane staining of any intensity in a section containing at least 100 tumor cells). The gene discussed is CD274; the disease is neoplasm.