A comparative study of INSM1 (clone MRQ70) immunoreactivity on CytoLyt® pretreated cytology and resection specimens of pancreatic neuroendocrine tumors

IF 1 4区医学 Q4 MEDICAL LABORATORY TECHNOLOGY

Diagnostic Cytopathology Pub Date : 2024-04-24 DOI:10.1002/dc.25328

Tiffany Jakowczuk BAS, Shuyue Ren MD, PhD

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引用次数: 0

Abstract

Introduction

Insulinoma-associated protein 1 (INSM1) is a newly characterized sensitive and specific immunohistochemical marker for neuroendocrine (NE) tumors. Whereas more traditional NE markers, such as chromogranin A and synaptophysin, are cytoplasmic, INSM1 is uniquely nuclear and thus could serve as a useful addition to NE tumor workup. While application of immunohistochemical studies to cytology specimens is becoming increasingly relevant, knowledge of the effects of the certain fixatives as well as the pattern and intensity of immunoexpression are important considerations.

Methods

Sixteen cases of pancreatic neuroendocrine tumor (PanNET) diagnosed between 2015 and 2021 underwent both fine-needle aspiration, which was subsequently prepared in CytoLyt®-fixed cytology cell block (CCB), and surgical resection, in which specimens were prepared into formalin-fixed paraffin embedded blocks (FFPE). For all samples, INSM1 immunoreactivity was classified according to staining intensity and extent, then compared between CCBs and matched FFPEs.

Results

All 16 FFPE specimens demonstrated strong and diffuse INSM1 immunoreactivity, while only 10/16 (62.5%) CCBs were positive. Of those 10, only 2/10 (20%) demonstrated strong and diffuse reactivity.

Conclusion

The choice of fixative has a demonstrable effect on the immunoreactivity of INSM1 in PanNET. Even though the sensitivity is lower in CytoLyt®-fixed cell block specimens, the addition of INSM1 is useful, especially in challenging cases that may be negative for one or more of the traditional NE markers.

Abstract Image

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胰腺神经内分泌肿瘤细胞学预处理标本和切除标本上 INSM1（克隆 MRQ70）免疫反应的比较研究。

简介胰岛素瘤相关蛋白 1（INSM1）是神经内分泌（NE）肿瘤新近发现的一种敏感而特异的免疫组化标记物。传统的 NE 标志物（如嗜铬粒蛋白 A 和突触素）具有细胞质特性，而 INSM1 则具有独特的细胞核特性，因此可作为 NE 肿瘤检查的有效补充。虽然免疫组化研究在细胞学标本中的应用正变得越来越重要，但了解某些固定剂的作用以及免疫表达的模式和强度也是重要的考虑因素。方法16例在2015年至2021年间确诊的胰腺神经内分泌肿瘤（PanNET）患者同时接受了细针穿刺抽吸术（随后制备成CytoLyt®固定的细胞学细胞块（CCB））和手术切除术（将标本制备成福尔马林固定的石蜡包埋块（FFPE））。结果所有 16 份 FFPE 标本都显示出强烈而弥漫的 INSM1 免疫反应，而只有 10/16 份（62.5%）CCB 标本呈阳性。结论固定液的选择对 PanNET 中 INSM1 的免疫反应有明显的影响。尽管 CytoLyt® 固定细胞块标本的灵敏度较低，但 INSM1 的添加还是很有用的，尤其是在一种或多种传统 NE 标记物阴性的高难度病例中。

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来源期刊

Diagnostic Cytopathology 医学-病理学

CiteScore

2.60

自引率

7.70%

发文量

163

审稿时长

3-6 weeks

期刊介绍： Diagnostic Cytopathology is intended to provide a forum for the exchange of information in the field of cytopathology, with special emphasis on the practical, clinical aspects of the discipline. The editors invite original scientific articles, as well as special review articles, feature articles, and letters to the editor, from laboratory professionals engaged in the practice of cytopathology. Manuscripts are accepted for publication on the basis of scientific merit, practical significance, and suitability for publication in a journal dedicated to this discipline. Original articles can be considered only with the understanding that they have never been published before and that they have not been submitted for simultaneous review to another publication.