Pagedar Nitin A, Chen Daniel H, Wasman Jay K, Savvides Panayiotis, Schluchter Mark D, Wilhelm Scott M, Lavertu Pierre
Department of Otolaryngology-Head and Neck Surgery, University Hospitals Case Medical Center, Case School of Medicine, Cleveland, Ohio 44106, USA.
Laryngoscope. 2008 Apr;118(4):692-6. doi: 10.1097/MLG.0b013e31815ed0ff.
Fine needle aspiration (FNA) biopsy of thyroid nodules provides cytologic specimens whose interpretation can direct patients toward either thyroidectomy or observation. Approximately 20% of FNA specimens yield an indeterminate result. Recent studies have characterized differences in gene expression between benign and malignant conditions, most often using whole tissue. Our goal was to determine the feasibility of quantitative polymerase chain reaction (qPCR)-based gene expression analysis in cytologic samples. For five genes shown to be over-expressed in thyroid carcinomas (fibronectin, galectin-3, Met/HGFR, MUC1, and GA733-precursor), we compared expression among pathologic states.
Prospective laboratory analysis of 20 thyroidectomy specimens.
Routine microscopy was performed. Cytologic samples were obtained from the dominant nodules, and RNA was extracted. Preliminary analysis using fluorometry and reverse-transcriptase (RT)-PCR was performed. Expression levels of the test genes in nodules and from control samples were measured by real-time qPCR. Fold changes in gene expression were compared.
Only one specimen did not yield sufficient intact RNA for gene expression analysis. RT-PCR revealed satisfactory RNA recovery in all other specimens. qPCR showed significant over-expression of fibronectin in the papillary carcinomas compared with the goiters (P = .0013), follicular adenomas (P = .0014), and follicular carcinomas (P = .0001). Differences in both fibronectin and MUC1 expression between the follicular carcinomas and the follicular adenomas were also significant (P = .025 and .045, respectively).
Cytologic specimens were a satisfactory source of tissue for qPCR-based gene expression analysis. Both fibronectin and MUC1 were differentially expressed in follicular adenomas and follicular carcinomas, and fibronectin expression differed in papillary carcinomas compared with the other lesions. These results may form the basis of a clinical predictor for lesions with indeterminate or suspicious cytology.
甲状腺结节细针穿刺抽吸（FNA）活检可提供细胞学标本，其解读结果可指导患者选择甲状腺切除术或观察。约20%的FNA标本会得出不确定结果。近期研究已明确了良性和恶性疾病之间基因表达的差异，多数研究采用的是全组织样本。我们的目标是确定基于定量聚合酶链反应（qPCR）的基因表达分析在细胞学样本中的可行性。对于在甲状腺癌中显示过表达的五个基因（纤连蛋白、半乳糖凝集素-3、Met/肝细胞生长因子受体、MUC1和GA733前体），我们比较了不同病理状态下的基因表达情况。
对20例甲状腺切除标本进行前瞻性实验室分析。
进行常规显微镜检查。从主要结节获取细胞学样本并提取RNA。使用荧光法和逆转录（RT）-PCR进行初步分析。通过实时qPCR测量结节及对照样本中检测基因的表达水平。比较基因表达的倍数变化。
仅1例标本未获得足够完整的RNA用于基因表达分析。RT-PCR显示所有其他标本的RNA回收情况良好。qPCR结果显示，与甲状腺肿（P = 0.0013）、滤泡性腺瘤（P = 0.0014）和滤泡性癌（P = 0.0001）相比，乳头状癌中纤连蛋白有显著过表达。滤泡性癌与滤泡性腺瘤之间纤连蛋白和MUC1表达的差异也具有统计学意义（分别为P = 0.025和0.045）。
细胞学标本是基于qPCR的基因表达分析的理想组织来源。纤连蛋白和MUC1在滤泡性腺瘤和滤泡性癌中存在差异表达，乳头状癌与其他病变相比纤连蛋白表达也有所不同。这些结果可能为细胞学检查结果不确定或可疑的病变提供临床预测指标的基础。
