biostudies-literatureQu SIntramural NIH HHSNational Cancer Institute141-153https://www.ebi.ac.uk/biostudies/studies/S-EPMC8692365biostudies-literatureUnknown17(1)<h4>Introduction</h4>A new molecular subtype classification was recently proposed for SCLC. It is necessary to validate it in primary SCLC tumors by immunohistochemical (IHC) staining and define its clinical relevance.<h4>Methods</h4>We used IHC to assess four subtype markers (ASCL1, NEUROD1, POU2F3, and YAP1) in 194 cores from 146 primary SCLC tumors. The profiles of tumor-associated CD3⁺ and CD8⁺ T-cells, MYC paralogs, SLFN11, and SYP were compared among different subtypes. Validation was performed using publicly available RNA sequencing data of SCLC.<h4>Results</h4>ASCL1, NEUROD1, POU2F3, and YAP1 were the dominant molecular subtypes in 78.2%, 5.6%, 7%, and 2.8% of the tumors, respectively; 6.3% of the tumors were negative for all four subtype markers. Notably, thrJournal of thoracic oncology : official publication of the International Association for the Study of Lung CancerMolecular Subtypes of Primary SCLC Tumors and Their Associations With Neuroendocrine and Therapeutic Markers.PMC8692365BC006161ZIA BC011787Z01 BC006161ZIA BC011839Schrump DSQu SPommier YThomas AChen HMiettinen MMFetsch PfalseMolecular Subtypes of Primary SCLC Tumors and Their Associations With Neuroendocrine and Therapeutic Markers.<h4>Introduction</h4>A new molecular subtype classification was recently proposed for SCLC. It is necessary to validate it in primary SCLC tumors by immunohistochemical (IHC) staining and define its clinical relevance.<h4>Methods</h4>We used IHC to assess four subtype markers (ASCL1, NEUROD1, POU2F3, and YAP1) in 194 cores from 146 primary SCLC tumors. The profiles of tumor-associated CD3⁺ and CD8⁺ T-cells, MYC paralogs, SLFN11, and SYP were compared among different subtypes. Validation was performed using publicly available RNA sequencing data of SCLC.<h4>Results</h4>ASCL1, NEUROD1, POU2F3, and YAP1 were the dominant molecular subtypes in 78.2%, 5.6%, 7%, and 2.8% of the tumors, respectively; 6.3% of the tumors were negative for all four subtype markers. Notably, thr2022-01-01T00:00:00Z2022 Jan2025-04-26T00:23:28.229Z2024-11-20T04:35:52.467ZS-EPMC86923653453468010.1016/j.jtho.2021.08.763