Supplementary Material for: Mixed Adenoneuroendocrine Carcinomas of the Gastrointestinal Tract: Targeted Next-Generation Sequencing Suggests a Monoclonal Origin of the Two Components

Background: Mixed adenoneuroendocrine carcinomas (MANECs) of the gastrointestinal tract are rare neoplasms characterized by coexisting exocrine and neuroendocrine neoplastic components. MANECs' histogenetic classification and molecular characterization remain unclear, significantly affecting the identification of innovative therapeutic options for these tumors. Methods: The exocrine and neuroendocrine components of 6 gastrointestinal MANECs were microdissected and subjected to the simultaneous mutation assessment in selected regions of 54 cancer-associated genes using Ion Torrent semiconductor-based next-generation sequencing. Sanger sequencing and immunohistochemistry were used as validation of the mutational status. Results: A total of 20 driver gene somatic mutations were observed among the 12 neoplastic components investigated. In 11 of 12 (91.7%) samples, at least one mutation was detected; 7 samples (58.3%) were found to have multiple mutations. TP53 gene mutations were the most frequent genetic alterations observed in the series, occurring in 11/12 samples (91.7%). Somatic mutations in other genes were detected at lower frequencies: ATM, CTNNB1, ERBB4, JAK3, KDR, KRAS, RB1. Conclusions: Five of the 6 MANECs presented an overlapping mutational profile in both components, suggesting a monoclonal origin of the two MANEC components.

背景：胃肠道混合腺神经内分泌癌（Mixed adenoneuroendocrine carcinomas, MANECs）是一类罕见肿瘤，以同时存在外分泌腺与神经内分泌两种肿瘤性成分为特征。目前MANECs的组织发生学分类与分子特征仍不明确，这极大限制了该类肿瘤创新治疗方案的开发与筛选。方法：本研究对6例胃肠道MANECs的外分泌腺及神经内分泌肿瘤成分进行显微切割，采用基于Ion Torrent半导体技术的下一代测序技术，对54个癌症相关基因的选定区域同步开展突变检测。同时采用桑格测序（Sanger sequencing）与免疫组化（immunohistochemistry）对突变状态进行验证。结果：本次研究分析的12份肿瘤性成分样本中，共检出20个驱动基因体细胞突变。12份样本中的11份（91.7%）可检测到至少1个突变，其中7份（58.3%）存在多个突变。TP53基因突变是本队列中最常见的遗传变异，在11份样本（91.7%）中被检出。其余基因的体细胞突变检出频率较低，包括ATM、CTNNB1、ERBB4、JAK3、KDR、KRAS及RB1。结论：6例MANECs中的5例，其两种肿瘤成分具有重叠的突变谱，提示该肿瘤的两种成分源自单克隆起源。