【作者】 史志周；

【导师】 王明荣；

【作者基本信息】 北京协和医学院 ， 细胞生物学， 2011， 博士

【摘要】 食管癌的死亡率在我国恶性肿瘤中居第四位,鳞状细胞癌是我国食管癌的主要病理类型,总体五年生存率仅约10%。为鉴定与食管癌发生发展相关的基因,我们检测了食管癌和癌前病变组织的DNA拷贝数改变,进而对预后相关的基因组改变进行了筛选和鉴定。本研究首先进行了比较基因组杂交芯片分析,结果显示与不典型增生相比,癌组织中存在更多的基因组改变。癌前病变和癌组织中共有的增益区段为3q、8q和11q13.3,缺失区段为3p、9p和9q,高水平扩增区段为7p11.2(SEC61G、EGFR和LANCL2)和11q13.3(CCND1等),纯合性缺失区段为9p21.3(CDKN2A和CDKN2B)。在Array CGH所检测的病例中,比较具有预后资料的长生存期组(大于45个月,n=24)和短生存期组(3-15月,n=11)的基因组改变频率,发现11q13.2的增益和7q34、18q21.1-q23的缺失与食管癌的不良预后相关。通过两套独立标本(n=151和84)的分析,结果均显示定位于11q13.2的基因CPT1A的拷贝数增加为肿瘤患者不良预后的独立预测因子。FISH和免疫组织化学的实验结果进一步证实CPT1A的增益和蛋白高表达与食管鳞癌的不良预后相关。11q13.3中的ANO1基因的扩增也与食管癌不良预后相关(n=35,P=.024)。在mRNA水平,从正常食管上皮、轻度不典型增生、中度不典型增生到浸润性食管癌中,ANO1的表达呈逐渐上升趋势。对食管癌及癌旁组织的免疫组织化学检测发现,该基因在25%的肿瘤比癌旁组织表达上调。采用RNAi的方法降低ANO1的表达可以促进食管鳞癌细胞系KYSE30的凋亡。以上结果说明,7p11.2、11q13.3的扩增和9p21.3的纯合性缺失是食管鳞癌发生阶段的早期事件,定位于1lql3的基因CPT1A和ANO1的拷贝数增加均与食管癌患者的较短生存时间相关,CPT1A的异常为不良预后的独立预测因子。更多还原

【Abstract】 Esophageal cancer is the fourth most common malignancy in China, and squamous cell carcinoma (ESCC) is the most prevalent type. Multiple changes have been found in ESCC, but little is known about major oncogenes and tumor suppressor genes involved in this disease. In the present study, we investigated the genomic alterations and prognosis relevance in esophageal squamous cell carcinoma.We analyzed the whole-genome copy number changes of 5 moderate dysplasias. 11 severe dysplasias and 79 ESCCs using oligo array comparative genomic hybridization (array CGH), and found that gains of 3q,8q, llq13.3 and losses of 3p, 9p,9q were common events in all the three types of samples. High-level amplifications of 7pl1.2 (SEC61G, EGFR, LANCL2), llq13.3 (CCND1,0RA0V1, FGF19, FGF4, FGF3, AN01, FADD, PPFIA1, CTTN, SHANK2) and homozygous deletion of 9p21.3 (CDKN2A, CDKN2B) existed in both ESCC and dysplasia.Gains of llq13.2 and losses of 7q34 and 18q21.1-q23 were associated with poor prognosis of ESCC. We selected the CPT1A and AN01 on Hql3 for further validation. In two independent sets of samples, copy number increase of CPT1A on Ilql3.2 was correlated with short overall survival (P-.015, n= 151 and P=.044, n = 84). Multivariate analysis confirmed that CPT1A gain provided prognostic information in ESCC (HR,1.643; 95% CI,1.076 to 2.509; P=.022; HR,2.488; 95% CI,1.235 to 5.013; P=.011). Immunohistochemistry assay showed significant correlation between strong expression of CPTl A protein and poor outcome of ESCC patients (P=.018, n= 73). Amplification of ANO1 located on Ilql3.3 was also associated with unfavorable outcome of ESCC (n= 35, P=.024). From the normal esophageal epithelium, mild dysplasia, moderate dysplasia to invisive squamous cell carcinoma, ANOl mRNA expression was gradually increased. IHC showed that ANOl was overexpressed in 25% of ESCCs compared to adjacent normal tissues. Down-regulation of ANOl can promote the apoptosis of KYSE30.Our results suggested that amplifiactions of 7p11,2, llq13.3 and homozygous deletion of 9p21.3 were the early events in the development of ESCC. Copy number increase of CPTIA and ANOl were correlated with short overall survival respectively, and CPTIA alteration was an independent poor prognosticator for the disease.更多还原