Ballmann Cora, Thiel Anne, Korah Hannah E, Reis Anna-Carinna, Saeger Wolfgang, Stepanow Stefanie, Köhrer Karl, Reifenberger Guido, Knobbe-Thomsen Christiane B, Knappe Ulrich J, Scholl Ute I
Department of Nephrology, School of Medicine, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
Department of Pathology and Neuropathology, University Hospital Essen, Essen, Germany.
J Endocr Soc. 2018 Feb 19;2(3):266-278. doi: 10.1210/js.2017-00364. eCollection 2018 Mar 1.
Gain-of-function somatic mutations in the ubiquitin specific protease 8 () gene have recently been reported as a cause of pituitary adenomas in Cushing disease. Molecular diagnostic testing of tumor tissue may aid in the diagnosis of specimens obtained through therapeutic transsphenoidal surgery; however, for small tumors, availability of fresh tissue is limited, and contamination with normal tissue is frequent. We performed molecular testing of DNA isolated from single formalin-fixed and paraffin-embedded (FFPE) tissue sections of 42 pituitary adenomas from patients with Cushing disease (27 female patients and 15 male patients; mean age at surgery, 42.5 years; mean tumor size, 12.2 mm). By Sanger sequencing, we identified previously reported missense mutations in six tumors. Targeted next-generation sequencing (NGS) revealed known or previously undescribed missense mutations in three additional tumors (two with two different mutations each), with mutant allele frequencies as low as 3%. Of the nine tumors with mutations (mutation frequency, 21.4%), seven were from female patients (mutation frequency, 25.9%), and two were from male patients (mutation frequency, 13.3%). Mutant tumors were on average 11.4 mm in size, and patients with mutations were on average 43.9 years of age. The overall mutation frequency in our cohort was lower than in previously described cohorts, and we did not observe deletions that were frequent in other cohorts. We demonstrate that testing for variants can be performed from small amounts of FFPE tissue. NGS showed higher sensitivity for mutation detection than did Sanger sequencing. Assessment for mutations may complement histopathological diagnosis.
泛素特异性蛋白酶8（USP8）基因的功能获得性体细胞突变最近被报道为库欣病垂体腺瘤的一个病因。肿瘤组织的分子诊断检测可能有助于通过经蝶窦治疗性手术获取的标本的诊断；然而，对于小肿瘤，新鲜组织的可获得性有限，且常被正常组织污染。我们对从42例库欣病患者的垂体腺瘤（27例女性患者和15例男性患者；手术时平均年龄42.5岁；平均肿瘤大小12.2mm）的单个福尔马林固定石蜡包埋（FFPE）组织切片中分离的DNA进行了分子检测。通过桑格测序，我们在6个肿瘤中鉴定出先前报道的错义突变。靶向二代测序（NGS）在另外3个肿瘤（其中2个肿瘤各有2种不同突变）中揭示了已知或先前未描述的错义突变，突变等位基因频率低至3%。在9个有USP8突变的肿瘤中（突变频率为21.4%），7个来自女性患者（突变频率为25.9%），2个来自男性患者（突变频率为13.3%）。突变肿瘤的平均大小为11.4mm，有突变的患者的平均年龄为43.9岁。我们队列中的总体USP8突变频率低于先前描述的队列，并且我们未观察到在其他队列中常见的USP8缺失。我们证明可以从少量FFPE组织中进行USP8变异检测。NGS对USP8突变检测的灵敏度高于桑格测序。USP8突变评估可能补充组织病理学诊断。
