CD274 and neoplasm: Several studies have confirmed that PD-L1 expression in cytological specimens from PE is highly consistent with that in lung tissue specimens, accurately reflecting the histological expression at the primary lung site.10 This study used immunocytochemical methods to detect PD-L1 expression in lung adenocarcinoma (LUAD) cells within PE, analyze the relationship between PD-L1 expression and DNA ploidy, and assess whether high PD-L1 expression enhances tumor cell proliferation and invasiveness.