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Insulinoma‐associated protein 1 expression in pancreatic neuroendocrine tumours in endoscopic ultrasound‐guided fine‐needle aspiration cytology: An analysis of 14 patients
Author(s) -
Takase Yorihiko,
Naito Yoshiki,
Okabe Yoshinobu,
Ishida Yusuke,
Yamaguchi Tomohiko,
Abe Hideyuki,
Murata Kazuya,
Ito Takaaki,
Tanigawa Masahiko,
Kawahara Akihiko,
Yano Hirohisa,
Akiba Jun
Publication year - 2019
Publication title -
cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 48
eISSN - 1365-2303
pISSN - 0956-5507
DOI - 10.1111/cyt.12640
Subject(s) - medicine , endoscopic ultrasound , cytology , insulinoma , neuroendocrine tumors , fine needle aspiration , adenocarcinoma , pathology , immunocytochemistry , radiology , pancreas , cancer , biopsy
Background Insulinoma‐associated protein 1 ( INSM 1) has been reported to be a useful marker for diagnosing pancreatic neuroendocrine tumours ( PNET s). However, INSM 1 expression in endoscopic ultrasound‐guided fine needle aspiration cytology has not been examined. We evaluated INSM 1 expression in the cytology of cases diagnosed with PNET s. Methods We immunocytochemically stained INSM 1 and Ki‐67 in 14 PNET cases, and according to the 2017 World Health Organisation criteria, seven PNET Grade 1 cases, four Grade 2 cases and three Grade 3/neuroendocrine carcinoma cases were identified. As a control for INSM 1 and Ki‐67 expression, we used cytological specimens from 15 cases of pancreatic ductal adenocarcinoma. Results In PNET cases, INSM 1‐expressing tumour cells were identified in all cytological specimens of PNET . The median INSM 1 expression rate in Grade 1 cases was 49.8% (mean ± standard deviation: 55.1 ± 12.5%, min: 39.3%, max: 74.1%), and in Grade 2 and Grade 3/neuroendocrine carcinoma cases was 81.1% (mean ± standard deviation: 77.6 ± 18.6%, min: 50.3%, max: 100%). However, there was no correlation between INSM 1 and Ki‐67 expression ( r = −0.15). The median expression rate in PNET cases was 64.3%, which was significantly higher than that in pancreatic ductal adenocarcinoma cases ( P < 0.0001). Conclusion INSM 1 immunocytochemistry of cytological specimens obtained from endoscopic ultrasound‐guided fine needle aspiration cytology can accurately diagnose PNET s; therefore, INSM 1 could be an important diagnostic tool in assessing therapeutic strategies, including molecular‐targeted therapy.