甲状腺乳头状癌（PTC）的发病率逐年增加，研究显示,伴有BRAF基因突变的PTC预后更差，检测BRAF基因突变有助于降低由于复发和转移造成的病死率。BRAF基因突变会引起细胞外基质改变，而后者也是肿瘤组织弹性的决定因素。剪切波弹性成像（SWE）是一种新的超声成像技术，我们前期研究发现，其不仅可用于PTC的鉴别诊断，也可预测PTC的转移。我们就此提出假设，SWE与BRAF基因突变相关，其机制部分与细胞外基质的改变有关。为验证该假设，本研究拟建立PTC的BRAF基因干扰裸鼠肿瘤模型，比较BRAF基因突变被干扰后肿瘤内细胞外基质和SWE参数的变化及裸鼠肿瘤转移的情况，研究BRAF基因突变及细胞外基质与SWE参数的相关性，探索SWE对PTC进行预后预测的机制。本研究对从基因层面阐明SWE对PTC预后的预测作用有重要意义，将提出一种全新的PTC术前风险评估及预后预测的模式。

The prevalence of the papillary thyroid cancer(PTC) has increased in recent years. Recent studies have established a strong association of BRAF mutation with adverse outcomes of PTC. BRAF mutation testing was useful to reduce the mortality due to metastases and recurrence. And the mechanism partly related to changes in the extracellular matrix(ECM). ECM is a determinant of tumor tissue elasticity.Shear wave elastography(SWE) is a new ultrasound technique. Our previous studies showed that SWE could be used to not only the differential diagnosis of the PTC, but also the prediction of the prognosis of the PTC. On the basis of that, we hypothesized that SWE parameters were associated with BRAF mutation and the mechanism partly related to changes in the ECM. We aimed to build a BRAF gene RNA interference nude mice tumor model to compare the changes of ECM and elastography parameters, and the tumor metastasis in the nude mice after the RNA interference of BRAF gene. Then, we are going to study the relationship between BRAF mutation, ECM and SWE parameters and explore the mechanism of SWE prediction of the prognosis of the PTC. This study is important to clarify the role of SWE in prediction of the prognosis of the PTC at the genetic level. The project will provide a new mode for the preoperative risk assessment and prediction of the prognosis of PTC.