候选区域乳头状甲状腺癌易感基因的精细定位和功能分析

Supported by National Science Foundation of China for young investigator, we have genotyped 845 papillary thyroid cancer (PTC) cases and 1000 controls for the association study of PTC susceptibility genes. The four chromosome regions 14q13.3, 9q22.33, 2q35 and 8p12 were indentified as the susceptibility loci of PTC in Chinese population( published at J Med Genet.2013). This project is based on the former works mentioned above, firstly, the four loci indentified above were target sequenced by next generation sequencing (NGS) technique PTC cases and normal controls to find the genetic variants. The phase one genotyping will include the functional variants indentified by NGS screening in 1000 PTC cases and 1000 normal controls. The genetic variants with significant associations will be genotyped in 3000 PTC cases and 3000 normal controls for the phase two validation. The variants indentified by combined analysis with significant association and related genes will be analyzed in cell and tissue based experiments. The gene and gene interactcion and gene and external effects interaction will be analyzed by stratification of iodine intake, life style and enviromental exposure. All these results will be used as the fundamental data of prevention of PTC. The prediction model of PTC in the patients of thyroid nodule will be made. The significance of prediction model which includes test of susceptibility gene, unltrasound examination, nuclear medical imaging, fine needle aspiration biopsy （FNAB） and BRAF mutation screening of FNAB samples will be discussed for the improvement of pre-operative diagnostic accuracy of thyroid nodule. This model will be used for the clinical management of thyroid nodule.

在青年基金的资助下，申请者对845例甲状腺乳头状癌（PTC）和1005 例正常对照进行了关联研究，发现染色体14q13.3、9q22.33、2q35、8p12区域为PTC的易感区域（J Med Genet，2013）。本研究拟利用二代测序技术对上述四个染色体区域进行深度测序确定遗传变异谱，对功能变异进行第一阶段1000PTC/1000对照的基因分型及第二阶段3000PTC/3000对照的大样本验证，并结合细胞学功能实验和不同基因型正常甲状腺组织易感基因的表达情况，确定易感基因，并研究遗传变异对其功能的影响。结合碘摄入、生活方式及环境等因素的分层分析，明确易感基因与环境的相互作用对PTC发病的影响，为PTC的预防提供依据。此外，在由超声、穿刺、核医学影像构成的传统甲状腺结节诊断模式上，评价加入血样的易感基因检测和穿刺样本的BRAF突变检测对提高术前诊断准确性的意义，改进甲状腺结节的诊治流程。

甲状腺癌是最常见的内分泌系统肿瘤，遗传因素是甲状腺癌发病的关键因素之一。课题负责人曾对845 例甲状腺乳头状癌（PTC）和1005 例正常对照进行了关联研究，发现染色体14q13.3、9q22.33、2q35、8p12 区域为PTC 的易感区域。该项目研究证实8p12区域的NRG1基因以癌基因的形式参与甲状腺癌的发生，并受rs2439302多态性的调控。鉴定了成熟microRNA序列多态性与甲状腺乳头状癌易感性的相关性。国际上首先对中国人群进行了甲状腺乳头状癌的全外显子组关联分析，通过对3334 PTC-7357正常对照组成的研究群体，三阶段的研究，发现了15个位点与中国人的PTC易感性相关（rs2516677、rs944289、rs151045610、rs1351164、rs965513、rs17089782、rs12129938、rs966423、rs2439302、rs4649295、rs72753537、rs11175834、rs2115386、rs16879552、rs7156229）。其中包括7个新的甲状腺乳头状癌的易感基因位点，5个位于未经报道的易感基因区域，验证了8个既往报道过的甲状腺癌的易感基因位点。该项目证实不同基因型的个体，所患甲状腺癌的临床病理特点有不同；在良性和恶性结节的比较中发现，随着危险等位基因数目的增加，恶性结节的可能性就越大，该研究可以用于临床甲状腺结节的个体化诊治。研究同时证实应用易感基因位点可以预测甲状腺癌的发病风险，结果可以用于预防策略的制定。项目执行期间发表8篇SCI论文，培养博士研究生4名，目前在读研究生4名。相关研究结果在《中国医学论坛报》、《大众卫生报》、搜狐网等媒体进行科普和报道。