Large-scale gene expression profiling of hepatocellular adenomas. Homo sapiens

Hepatocellular adenomas (HCA) are rare benign tumors mainly developed in women after 2 years of oral contraceptive use (Rooks et al., 1979). HCA are also related to other risk factors (obesity, vascular diseases, androgen and alcohol intake) or to different genetic diseases (Mac Cune Albright syndrome, glycogen storage diseases type 1a and MODY3 diabetes caused by HNF1A germline mutation) (Calderaro et al., 2013; Nault et al., 2013a). Bleeding and malignant transformation to hepatocellular carcinoma (HCC) can occur as severe complications observed respectively in 30-50% and 5% of the cases. In the past 10 years, we identified 4 major molecular subgroups of HCA defined by (1) mutations inactivating HNF1A (H-HCA, 35% of the HCA) (Bacq et al., 2003; Bluteau et al., 2002; Jeannot et al., 2010), (2) activation of ß-catenin by mutations in exon 3 (bHCA, 15%) (Chen et al., 2002), (3) inflammatory phenotype with STAT3 activation (IHCA, 50%) (Bioulac-Sage et al., 2009; Zucman-Rossi et al., 2006), (4) a tumor subgroup of HCA with Sonic Hedgehog pathway activation due to recurrent focal deletions (shHCA) (Nault et al. ,in preparation) and (5) the remaining unclassified tumors (UHCA, 10%) (Bioulac-Sage et al., 2009). Among bHCA, half displayed both inflammatory and ß-catenin activated phenotypes (bIHCA). Inflammatory adenomas (IHCA) are caused by IL6ST somatic mutation activating gp130 in 60% of the cases (Rebouissou et al., 2009) whereas other IHCA are mutated for STAT3 itself (Pilati et al., 2011) or GNAS (Nault et al., 2012) but in the remaining 30% cases no mutation (NM) were identified yet. This molecular classification is currently accepted in clinical practice using either immunohistochemical markers (Bioulac-Sage et al., 2009; Bioulac-Sage et al., 2007) or in radiology at MRI (Laumonier et al., 2008) and it has dramatically improved the diagnosis and prognostic assessment of HCA. HCC derived from HCA malignant transformation (HCC on HCA, 5%) Overall design: HCA liver tumors corresponding to 35 patients. In all cases, tumor samples were frozen (-80°C) after hepatic resection at diagnosis. Normal liver samples were used as reference samples. Comparative gene expression analysis was done using Affymetrix U133plus v2 array (GPL570)

肝细胞腺瘤（Hepatocellular adenomas, HCA）是一类罕见良性肿瘤，主要见于口服避孕药使用2年以上的女性（Rooks等，1979）。HCA还与多种其他危险因素相关，包括肥胖、血管疾病、雄激素摄入及饮酒，亦可继发于多种遗传疾病，如麦库恩-奥尔布赖特综合征（Mac Cune Albright syndrome）、1a型糖原贮积症以及由HNF1A生殖系突变导致的青少年起病的成人型糖尿病3型（MODY3）（Calderaro等，2013；Nault等，2013a）。出血以及向肝细胞癌（hepatocellular carcinoma, HCC）的恶性转化是其严重并发症，发生率分别为30%~50%和5%。
近十年来，本团队已明确HCA的分子分型体系，具体分型如下：(1) 携带HNF1A失活突变的亚型（H-HCA，占HCA的35%）（Bacq等，2003；Bluteau等，2002；Jeannot等，2010）；(2) 因3号外显子突变导致β-连环蛋白（β-catenin）激活的亚型（bHCA，占15%）（Chen等，2002）；(3) 表现为炎性表型且STAT3激活的亚型（IHCA，占50%）（Bioulac-Sage等，2009；Zucman-Rossi等，2006）；(4) 因复发性局灶性缺失导致Sonic Hedgehog（Shh）通路激活的HCA亚型（shHCA，Nault等，待发表）；(5) 剩余未分类肿瘤（UHCA，占10%）（Bioulac-Sage等，2009）。其中，bHCA中有半数同时表现出炎性表型和β-连环蛋白激活特征（bIHCA）。
炎性腺瘤（IHCA）中，60%的病例是因IL6ST体细胞突变激活gp130所致（Rebouissou等，2009），其余IHCA则存在STAT3自身突变（Pilati等，2011）或GNAS突变（Nault等，2012），但剩余30%的病例尚未检测到突变（NM）。该分子分类目前已在临床实践中得到广泛认可，可通过免疫组化标记物（Bioulac-Sage等，2009；Bioulac-Sage等，2007）或磁共振成像（MRI）影像学检查实现分型（Laumonier等，2008），极大地改善了HCA的诊断与预后评估水平。由HCA恶性转化而来的肝细胞癌（即合并HCA的肝细胞癌，HCC on HCA）占比为5%。
整体实验设计：本研究纳入35例患者的HCA肝肿瘤样本。所有样本均为确诊时经肝切除获取的组织，术后冻存于-80℃环境。以正常肝组织作为对照样本。采用Affymetrix U133plus v2芯片（GPL570）完成对比基因表达分析。