Sahnane Nora, Furlan Daniela, Monti Matilde, Romualdi Chiara, Vanoli Alessandro, Vicari Emanuela, Solcia Enrico, Capella Carlo, Sessa Fausto, La Rosa Stefano
Section of Anatomic PathologyDepartment of Surgical and Morphological Sciences, University of Insubria, Via O. Rossi, 9, 21100 Varese, ItalyCRIBI Biotechnology CenterUniversity of Padova, Padova, ItalyDepartment of Molecular MedicineInstitute of Pathology, University of Pavia, IRCCS Policlinico San Matteo, Pavia, ItalyDepartment of PathologyOspedale di Circolo, Varese, Italy.
Section of Anatomic PathologyDepartment of Surgical and Morphological Sciences, University of Insubria, Via O. Rossi, 9, 21100 Varese, ItalyCRIBI Biotechnology CenterUniversity of Padova, Padova, ItalyDepartment of Molecular MedicineInstitute of Pathology, University of Pavia, IRCCS Policlinico San Matteo, Pavia, ItalyDepartment of PathologyOspedale di Circolo, Varese, Italy
Endocr Relat Cancer. 2015 Feb;22(1):35-45. doi: 10.1530/ERC-14-0410. Epub 2014 Dec 2.
Gastroenteropancreatic (GEP) neuroendocrine carcinomas (NECs) and mixed adenoneuroendocrine carcinomas (MANECs) are heterogeneous neoplasms characterized by poor outcome. Microsatellite instability (MSI) has recently been found in colorectal NECs showing a better prognosis than expected. However, the frequency of MSI in a large series of GEP-NEC/MANECs is still unknown. In this work, we investigated the incidence of MSI in GEP-NEC/MANECs and characterized their clinicopathologic and molecular features. MSI analysis and immunohistochemistry for mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) were performed in 89 GEP-NEC/MANECs (six esophageal, 77 gastrointestinal, three pancreatic, and three of the gallbladder). Methylation of 34 genes was studied by methylation-specific multiplex ligation probe amplification. Mutation analysis of BRAF and KRAS was assessed by PCR-pyrosequencing analysis. MSI was observed in 11 NEC/MANECs (12.4%): seven intestinal and four gastric. All but two MSI-cases showed MLH1 methylation and loss of MLH1 protein. The remaining two MSI-cancers showed lack of MSH2 or PMS2 immunohistochemical expression. MSI-NEC/MANECs showed higher methylation levels than microsatellite stable NEC/MANECs (40.6% vs 20.2% methylated genes respectively, P<0.001). BRAF mutation was detected in six out of 88 cases (7%) and KRAS mutation was identified in 15 cases (17%). BRAF mutation was associated with MSI (P<0.0008), while KRAS status did not correlate with any clinicopathologic or molecular feature. Vascular invasion (P=0.0003) and MSI (P=0.0084) were identified as the only independent prognostic factors in multivariate analysis. We conclude that MSI identifies a subset of gastric and intestinal NEC/MANECs with distinct biology and better prognosis. MSI-NEC/MANECs resemble MSI-gastrointestinal adenocarcinomas for frequency, molecular profile and pathogenetic mechanisms.
胃肠胰（GEP）神经内分泌癌（NECs）和混合性腺神经内分泌癌（MANECs）是预后较差的异质性肿瘤。最近在结直肠NECs中发现微卫星不稳定性（MSI），其预后比预期更好。然而，在大量GEP-NEC/MANECs中MSI的频率仍不清楚。在这项研究中，我们调查了GEP-NEC/MANECs中MSI的发生率，并对其临床病理和分子特征进行了表征。对89例GEP-NEC/MANECs（6例食管、77例胃肠道、3例胰腺和3例胆囊）进行了MSI分析和错配修复蛋白（MLH1、MSH2、MSH6和PMS2）的免疫组织化学检测。通过甲基化特异性多重连接探针扩增研究了34个基因的甲基化情况。通过PCR-焦磷酸测序分析评估BRAF和KRAS的突变情况。在11例NEC/MANECs（12.4%）中观察到MSI：7例肠道型和4例胃型。除2例MSI病例外，所有病例均显示MLH1甲基化和MLH1蛋白缺失。其余2例MSI癌症显示MSH2或PMS2免疫组化表达缺失。MSI-NEC/MANECs的甲基化水平高于微卫星稳定的NEC/MANECs（分别为40.6%和20.2%的甲基化基因，P<0.001）。在88例病例中的6例（7%）检测到BRAF突变，15例（17%）鉴定出KRAS突变。BRAF突变与MSI相关（P<0.0008），而KRAS状态与任何临床病理或分子特征均无相关性。在多变量分析中，血管侵犯（P=0.0003）和MSI（P=0.0084）被确定为仅有的独立预后因素。我们得出结论，MSI可识别出一部分具有独特生物学行为和较好预后的胃和肠道NEC/MANECs。MSI-NEC/MANECs在频率、分子谱和发病机制方面类似于MSI胃肠道腺癌。
