Common IHC markers for LUAD (whether solid or cystic) include NapsinA, Cytokeratin 7(CK7), and Thyroid Transcription Factor-1 (TTF-1); for adeno-squamous carcinoma, markers include p63, CK7, and CK5/6; for LUSC, markers include p63, CK5/6, and p40; and for SCLC, markers include CD56 and Synaptophysin (Kim et al., 2019; Dijkstra et al., 2020). The gene discussed is KRT5; the disease is small cell lung carcinoma.