Ito T, Kudoh S, Fujino K, Sanada M, Tenjin Y, Saito H, Nakaishi-Fukuchi Y, Kameyama H, Ichimura T, Udaka N, Kudo N, Matsuo A, Sato Y. Pulmonary Neuroendocrine Cells and Small Cell Lung Carcinoma: Immunohistochemical Study Focusing on Mechanisms of Neuroendocrine Differentiation.
Acta Histochem Cytochem 2022;
55:75-83. [PMID:
35821751 PMCID:
PMC9253501 DOI:
10.1267/ahc.22-00031]
[Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 04/12/2022] [Indexed: 12/03/2022] Open
Abstract
Neuroendocrine (NE) differentiation has been histochemically detected in normal and cancer tissues and cells. Immunohistochemical analyses have provided a more detailed understanding of NE biology and pathology. Pulmonary NE cells are a rare lung epithelial type, and small cell carcinoma of the lung (SCLC) is a high-grade NE tumor. Pulmonary NE and SCLC cells share common mechanisms for NE differentiation. Neural or NE cell lineage-specific transcription factors, such as achaete-scute homologue 1 (Ascl1) and insulinoma-associated protein 1 (INSM1), are crucial for the development of pulmonary NE cells, and NE differentiation is influenced by the balance between Ascl1 and the suppressive neural transcription factor, hairy-enhancer of split 1, a representative target molecule of the Notch signaling pathway.
In this review, we discuss the importance of Ascl1 and INSM1 in identifying pulmonary NE and SCLC cells and introduce Ascl1-related molecules detected by comparative RNA-sequence analyses. The molecular classification of SCLC based on the expression of lineage-specific transcription or co-transcription factors, including ASCL1, NEUROD1, POU2F3, and YAP1, was recently proposed. We attempted to characterize these 4 SCLC subtypes using integrated immunohistochemical studies, which will provide insights into the molecular characteristics of these subtypes and clarify the inter- and intratumor heterogeneities of SCLC.
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