The Chromogen Siblings return to talk about small cell lung carcinomas. Drs. Mike Arnold (@MArnold_PedPath),  Andrew Bellizzi (@IHC_guy), and Sanam Loghavi (@sanamloghavi) speak with Dr. Natasha Rekhtman (@natasharekhtman) of Memorial Sloan Kettering Cancer Center. Hear about how Pathologists use IHC to identify subsets of small cell lung carcinomas, and the cycle of how molecular data informs IHC approaches and histologic classifications in Pathology. Featured articles:  SCLC Subtypes Defined by ASCL1, NEUROD1, POU2F3, and YAP1: A Comprehensive Immunohistochemical and Histopathologic Characterization https://www.jto.org/article/S1556-0864(20)30755-3/fulltext POU2F3 in SCLC: Clinicopathologic and Genomic Analysis With a Focus on Its Diagnostic Utility in Neuroendocrine-Low SCLC https://linkinghub.elsevier.com/retrieve/pii/S1556-0864(22)00299-4 Featured public domain music: Alpha Hydrae, Won’t see it comin’