Takase Yorihiko, Naito Yoshiki, Okabe Yoshinobu, Ishida Yusuke, Yamaguchi Tomohiko, Abe Hideyuki, Murata Kazuya, Ito Takaaki, Tanigawa Masahiko, Kawahara Akihiko, Yano Hirohisa, Akiba Jun
Department of Diagnostic Pathology, Kurume University Hospital, Kurume, Japan.
Department of Pathology, Kurume University School of Medicine, Kurume, Japan.
Cytopathology. 2019 Mar;30(2):194-200. doi: 10.1111/cyt.12640. Epub 2018 Dec 17.
Insulinoma-associated protein 1 (INSM1) has been reported to be a useful marker for diagnosing pancreatic neuroendocrine tumours (PNETs). However, INSM1 expression in endoscopic ultrasound-guided fine needle aspiration cytology has not been examined. We evaluated INSM1 expression in the cytology of cases diagnosed with PNETs.
We immunocytochemically stained INSM1 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 INSM1 and Ki-67 expression, we used cytological specimens from 15 cases of pancreatic ductal adenocarcinoma.
In PNET cases, INSM1-expressing tumour cells were identified in all cytological specimens of PNET. The median INSM1 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 INSM1 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).
INSM1 immunocytochemistry of cytological specimens obtained from endoscopic ultrasound-guided fine needle aspiration cytology can accurately diagnose PNETs; therefore, INSM1 could be an important diagnostic tool in assessing therapeutic strategies, including molecular-targeted therapy.
胰岛素瘤相关蛋白1（INSM1）已被报道为诊断胰腺神经内分泌肿瘤（PNETs）的有用标志物。然而，内镜超声引导下细针穿刺细胞学检查中INSM1的表达尚未得到研究。我们评估了经诊断为PNETs的病例细胞学中INSM1的表达情况。
我们对14例PNET病例进行了INSM1和Ki-67免疫细胞化学染色，并根据2017年世界卫生组织标准，确定了7例1级PNET病例、4例2级病例和3例3级/神经内分泌癌病例。作为INSM1和Ki-67表达的对照，我们使用了15例胰腺导管腺癌的细胞学标本。
在PNET病例中，所有PNET细胞学标本中均鉴定出表达INSM1的肿瘤细胞。1级病例中INSM1的中位表达率为49.8%（平均值±标准差：55.1±12.5%，最小值：39.3%，最大值：74.1%），2级和3级/神经内分泌癌病例中为81.1%（平均值±标准差：77.6±18.6%，最小值：50.3%，最大值：100%）。然而，INSM1与Ki-67表达之间无相关性（r = -0.15）。PNET病例中的中位表达率为64.3%，显著高于胰腺导管腺癌病例（P < 0.0001）。
内镜超声引导下细针穿刺细胞学检查获得的细胞学标本进行INSM1免疫细胞化学检查可准确诊断PNETs；因此，INSM1可能是评估包括分子靶向治疗在内的治疗策略的重要诊断工具。
