Small cell lung cancer in a cytological smear: a) haematoxylin and eosin staining, b) positive immunohistochemistry (IHC) reaction with CD56, cell block. Adenocarcinoma with acinar pattern, tissue biopsy: c) haematoxylin and eosin staining, d) positive IHC reaction with napsin A. Squamous cell carcinoma, with typical features in a cytological smear: e) haematoxylin and eosin staining, f) positive IHC reaction with p40. g) Programmed death-ligand 1 (PD-L1) expression on nonsmall cell lung cancer cells in cellblock. Tumour proportion score >50, antibody: Ventana SP-263 (author's material).