CD274 and neoplasm: The level of PD-L1 expression, assessed using Ventana SP263 monoclonal antibody assay, was defined by the tumor proportion score (TPS) as high expression (TPS ≥ 50%), low expression (TPS 1%-49%) and no expression (TPS < 1%).<h4>Results</h4>101 (52.9%) of 191 advanced NSCLC patients were never smokers.