甲状腺乳头状癌中BRAFV599E点突变与RET/PTC融合基因的检测

目的检测甲状腺乳头状癌(PTC)及其他类型甲状腺良恶性肿瘤中BRAFV599E的点突变及 RET/PTC1、3融合基因的表达状况,探讨二者与PTC临床病理学特征的关系.方法用聚合酶链反应(PCR)及逆转录(RT)-PCR分别检测95例石蜡与新鲜甲状腺病变组织中BRAFV599E点突变和RET/PTC1、3融合基因.结果 (1)仅在PTC中检测到BRAFV599E的突变,突变率56%(37/66),在经典型PTC和高细胞型PTC中突变率分别为70%(29/41)和2/3,在滤泡型PTC及其他类型甲状腺病变中未检测到BRAFV599E的突变.统计学分析BRAF突变与性别、年龄、伴慢性淋巴细胞浸润及淋巴结转移无明显关系(P>0.05).(2)PTC中RET/PTC检出率21.2%(14/66),其中5例RET/PTC1阳性(7.6%),9例RET/PTC3阳性(13.6%).RET/PTC融合基因阳性的14例PTC中未检测到BRAFV599E突变.其余29例良恶性病例中未检测到RET/PTC融合基因.RET/PTC融合基因的表达与PTC的临床病理学特征无明显关系(P>0.05).结论 (1)BRAFV599E突变和RET/PTC融合基因是PTC较特征性的遗传学改变,可作为PTC诊断和鉴别诊断提供分子学的依据,BRAFV599E突变可能是甲状腺乳头状癌表型的重要决定因素之一;(2)BRAFV599E突变与PTC的经典型和高细胞型两种主要亚型密切相关;(3)BRAFV599E突变与RET/PTC融合基因可能在PTC中是独立事件.

BRAFV599E mutation and RET/PTC rearrangements in papillary thyroid carcinoma

OBJECTIVE: To detect the BRAF(V599E) mutation and the RET/PTC chimeric gene in benign and malignant thyroid diseases and to explore their correlation with the clinicopathologic features of papillary thyroid carcinoma (PTC). METHODS: PCR and RT-PCR were employed to detect BRAF(V599E) mutation and RET/PTC chimeric genes in 95 frozen and parraffine-embeded thyroid tissue. RESULTS: (1) BRAF(V599E) mutation was detected only in PTC (56%, 37/66) and had a high prevalence in both classic and tall cell types (70%, 29/41 and 2/3). However, follicular types of PTC and other benign and malignant thyroid diseases were negative for BRAF(V599E) mutation. (2) Fourteen (21.2%) PTC cases expressed RET/PTC chimeric gene. Among them, 5 cases (7.6%) were RET/PTC1 and 9 cases (13.6%) were RET/PTC3 respectively. (3) Statistic data did not show any correlation between the BRAF(V599E) mutation, RET/PTC and clinicopathologic features of PTC (P > 0.05). There was no overlap between BRAF(V599E) mutation and RET/PTC rearrangements. CONCLUSIONS: (1) BRAF(V599E) mutation and RET/PTC rearrangements were unique to PTC. The high prevalence of BRAF(V599E) mutation indicates that it is an important molecular hallmark of PTC. (2) BRAF(V599E) mutation rate was high in classic type PTC and tall cell type inferred that BRAF(V599E) mutation played an important role in their etiopathogenesis. (3) There was no overlap between BRAF(V599E) mutation and RET/PTC rearrangements suggest that they are alternative events in PTC.