CCDC6-RET融合基因在分化型甲状腺癌中的作用与机制研究

we performed whole-exome sequencing to investigate mutation landscape and the clonal origin of separated tumor foci aroused from the same thyroid carcinoma patient. A CCDC6-RET fusion rearrangement mutation was identified from a patient who had an invasive papillary thyroid carcinoma with metastases to the cervical lymph nodes. The rearrangement was caused by fusing the exon 1 of CCDC6 and the exon 12-20 of RET gene, which led to constitutive activation of the tyrosine kinase domain of RET, and uncontrolled activation of downstream proliferative signaling pathways. The role of CCDC6-RET in thyroid carcinoma is not fully understood, and whether CCDC6-RET can be targeted by the current clinically available tyrosine kinase inhibitors remains to be investigated. By taking advantage of our great cancer tissue bank we are applying to start a comprehensive study to investigate CCDC6-RET fusion in Thyroid carcinoma. This study will determine the prevalence of CCDC6-RET fusion in thyroid cancer patients and its relevance in different clinical stages and histographic types. Then, We will focus on the role of CCDC6-RET fusion in thyroid cancer by using established in vitro and in vivo models. We also will evaluate whether tumors driven by CCDC6-RET mutation can be targeted by Tyrosine kinase inhibitors. Above all, this study will not only provide insight into the basic molecular mechanisms of CCDC6-RET fusion in thyroid cancers, but also has a great potential to develop a treatment for thyroid cancers driven by CCDC6-RET.

我们利用外显子组测序鉴定分析了甲状腺乳头状癌不同病灶的基因突变与克隆起源的关系，在确定甲状腺癌相关突变基因数量和种类的基础上同时鉴定出一个RET和CCDC6的融合基因。该类型患者淋巴结转移率明显偏高且预后不良，据文献报道，融合可导致RET基因编码蛋白酪氨酸激酶结构域的激活，从而对下游信号通路造成影响。为了揭示CCDC6-RET融合基因在甲状腺癌中的生物学作用和分子调控机制，我们将利用大样本的甲状腺癌组织样本，鉴定和验证CCDC6-RET融合基因在分化型甲状腺癌中出现的频率，比较分化型甲状腺癌中融合基因的表达变化及其与临床分期和病理学特征的关系；在此基础上，通过基因克隆，测序、真核表达载体构建、细胞转染以及动物模型分析该融合基因的生物学特性与作用机制；从而阐释CCDC6-RET融合基因与分化型甲状腺癌病理学分型、临床分期及预后的关系，制定出分化型甲状腺癌临床诊治的规范。

甲状腺乳头状癌是内分泌系统中发病率最高的恶性肿瘤，发病率在近30年的时间里上升了3倍。体细胞遗传变异是甲状腺乳头状癌致病的决定性因素，鉴定癌组织的体细胞遗传变异对于甲状腺乳头状癌的精准诊断、治疗和预后判断至关重要。我们在前期工作的基础上，.检测了355例甲状腺乳头状癌中RET基因的表达情况；分析了甲状腺乳头状癌携带CCDC6-RET融合基因与临床病理学特征之间的关系；分析了甲状腺乳头状癌携带携带RET融合基因与临床病理学特征之间的关系；分析了中国人与西方人的甲状腺乳头状癌遗传背景异同及其与临床病理特征之间的关系；探究了多灶性甲状腺乳头状癌中T细胞受体β链组库与突变背景的联系；对合并桥本甲状腺炎的甲状腺乳头状癌的研究进展进行了综述；分析了携带BRAF突变的合并桥本甲状腺炎的甲状腺乳头状癌患者的临床病理特征；对侵袭性甲状腺乳头状癌的转录组表达特征进行了分析。本课题进行过程中探索设计的基因检测芯片可以用来鉴别甲状腺结节的良恶性，是基于中国人群的发病特点及遗传突变谱开发出来的；从合并桥本甲状腺炎及携带BRAF突变的角度，对甲状腺乳头状癌进行了分类，为指导患者预后提供了方法；此外，甲状腺乳头状癌的治疗难点在于预测高危类型及诊治复发难治性甲状腺乳头状癌患者，本课题组对此问题进行了探究，发现肿瘤浸润淋巴细胞对突变负荷比较低的肿瘤亦有识别作用，这为接下来用免疫治疗的方法探索治疗转移性甲状腺乳头状癌提供了依据；通过对侵袭性甲状腺乳头状癌转录组的分析，为预测患者的预后提供了一条途径。