BRAFV600E Mutation Analysis of Liquid Based Preparation-Processed Fine-Needle Aspiration Sample Improves the Diagnosis of Papillary Thyroid Carcinoma
HY Chang, A Kim, H Kim, H Lee, BH Kim. Korea University, Guro Hospital, Seoul, Korea
Background: Early detection and diagnosis of papillary carcinoma is important in the management of patients with thyroid nodule. Fine-needle aspiration (FNA) is the most useful tool in diagnosis of thyroid nodules, however 10 to 30% of papillary carcinomas are diagnosed as benign or indeterminate nodules by cytomorphologic examination alone. In recent years, liquid-based preparation (LBP, ThinprepR) in fine needle aspiration of thyroid nodule has been widely used and replacing conventional smear, because residual samples can be used for ancillary tests. BRAFV600E mutation is common and specific genetic alteration of papillary carcinoma. Detection of BRAFV600E mutation in cytology specimen could help diagnosis of papillary carcinoma. We analyzed cytologic features and BRAFV600E mutation status using thyroid LBP-FNA samples.
Design: A total of 191 histologically confirmed thyroid LBP-FNA specimens were selected. We analyzed cytomorpholoigic features and BRAFV600E mutation status in both LBP-FNA samples and their corresponding formalin-fixed paraffin-embedded tissue. Melting curve analysis (MCA) with SYBR green and SeeplexR BRAF ACE detection kit were used to detect BRAFV600E mutation.
Results: In 191 patients, 125 were histologically confirmed papillary carcinoma and 64 were benign lesions and carcinomas of other types. In tissue samples of papillary carcinomas, BRAFV600E mutation was detected in 71(56.8%) using BRAF kit and in 98(78.4%) cases using MCA. Only one benign tissue sample showed BRAFV600E mutation in MCA. Using residual cytologic material, BRAFV600E mutation was detected in 95(76%) using BRAF kit and in 98(78.4%) using MCA in histologically confirmed papillary carcinoma. Using LBP cytology alone, the sensitivity for diagnosis of papillary carcinoma was 70.4%. When BRAFV600E mutation analysis was done in conjunction with cytologic diagnosis, the diagnostic sensitivity of papillary carcinoma was increased to 84% and 86.4%(BRAF kit and MCA, respectively). In both methods, 3 benign cytologic samples showed BRAFV600E mutation.
Conclusions: This is the first study of validating the utility of BRAFV600E mutation in the diagnosis of thyroid papillary carcinoma using LBP-FNA samples. Liquid-based preparation for thyroid nodule makes it possible for ancillary tests such as immunochemistry (IC) and molecular tests without any further invasive examination by using residual material. And BRAFV600E mutation analysis may be a useful additional diagnostic tool for diagnosis of thyroid papillary carcinoma.
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 41, Tuesday Afternoon