Representatives of hematoxylin–eosin (H&E) staining and fluorescence in situ hybridization (FISH) in non–small cell lung cancer (NSCLC) lesions with anaplastic lymphoma kinase (ALK) rearrangement. a An ALK-rearranged adenocarcinoma with a mucinous pattern by H&E staining (×200). b An ALK-rearranged squamous carcinoma with a solid growth pattern by H&E staining (×200). c
ALK break-apart signals by FISH with a split orange (staining 3′-2 chromosomal/DNA region) and green (staining 5′-2 chromosomal/DNA region) signal pattern (red arrows), indicating an ALK rearrangement-positive status. d
ALK break-apart signals by FISH with an isolated orange signal pattern (yellow arrows), indicating an ALK rearrangement-negative status.