甲状腺多结节性增生的克隆性分析

Clonality analysis of thyroid multinodular hyperplasia

目的分析甲状腺结节状增生、甲状腺多发性腺瘤样结节和甲状腺结节状增生背景上的腺瘤样增生结节的克隆起源,为甲状腺多结节性增生的临床诊断和治疗提供依据。方法采用激光捕获显微切割技术及基于HUMARA基因多态性克隆性分析检测5例甲状腺结节状增生、5例甲状腺腺瘤、12例甲状腺多发性腺瘤样结节、15例甲状腺结节状增生背景上的腺瘤样增生结节是否为肿瘤性增生。结果HUMARA基因杂合率为86.5%(32/37)。5例单纯结节状增生为多克隆,5例单发包膜完整的腺瘤中1例为HUMARA基因纯合子,其余4例为单克隆。12例多发性腺瘤样结节中2例为HUMARA纯合子,4例多发腺瘤样结节中有多克隆性结节(1/3,1/3,1/2,2/2),其中4枚包膜包裹不完整,其余6例多枚结节均为单克隆且包膜完整。15例甲状腺结节状增生背景上的腺瘤样增生结节中2例为HUMARA纯合子,另13例结节状增生背景均为多克隆,其中8例结节为多克隆(3例无包膜,5例包膜不完整),余5例为单克隆(包膜完整)。结论克隆性分析有助于甲状腺结节状增生和腺瘤的鉴别,而多发性腺瘤和结节状增生伴腺瘤形成的诊断还需要结合包膜的完整性做出判断。

Purpose To investigate the clonal histogenesis of thyroid adenomatoid hyperplasia in nodular hyperplasia, multi-thyroid adenomas and adenomatoid nodules to provide evidences for the linical diagnosis and treatment of the nodular hyperplasia. Methods Thirty-seven thyroid multi-nodular hyperplasia were analyzed, including 5 cases of nodular goiter, 5 simple adenomas, 12 multi-thyroid adenomas, and 15 thyroid nodular goiter with adenomatoid nodules. Pure target cells were isolated by laser capture microdissection （LCM） from the routine sections stained with hematoxylin and eosin. Genomic DNA was extracted and digested with a methylation-sensitive restriction endonuclease （Hpa Ⅱ ）, and then human androgen receptor gene （HUMARA） amplified by PCR. The products were analyzed by denaturing polyacrylamide gels and visualized with silver staining. Results Heterozygosity of the HUMARA was found in 32/37 （86. 5% ） cases. Homozygosity of the thyroid was observed in 5/37 （ 13.5% ） cases, which were excluded from the clonality analysis. 5 nodular goiter samples presented polyclonal X-inactivation patterns （ 5/5 ） ; except for one case of homozygote （ 1/5 ）, thyroid simple adenoma tissues were monoclonal （4/5） ; of 12 multi-thyroid adenomas, 2 cases were homozygote, 4 cases had one or two polyclonal adenoma nodules （1/3,1/3,1/2,2/2） and four of these nodules surrounded by partial capsule, 6 cases exhibited monoclonal and all nodules had encapsulated （6/12） ; Among 15 adenomatoid nodules in nodular goiter samples, 2 cases were homozygote, 8 cases were polyclonal （ three of nodules without capsule, the others without complete encapsulation） and 5 cases were monoclonal （encapsulted）, 13 adenomatoid nodule-surrounding tissues （nodular goiter） were polyclonal. Conclutions The results suggest that clonality analysis has advantage in the differential diagnosis of thyroid nodular goiter from adenoma. Diagnosis of thyroid muhi-adenomas and nodular goiter with adenoma formation should be based on completeness of the capsule .