[432] Prediction of Malignant Lesions by a Set of Four miRNAs in Thyroid Fine Needle Aspiration Specimens.

Rulong Z Shen, Liyanarachchi Sandya, Wei Li, Paul E Wakely Jr, Motoyasu Saji, Jie Huang, Rebecca Nagy, Tisha Farrell, Matthew D Ringel, Richard T Kloos, Albert de la Chapelle, Huiling He. The Ohio State University, Columbus

Background: Cytological examination of thyroid nodules on fine needle aspiration (FNA) biopsies cannot reliably distinguish benign from malignant lesions for follicular patterned lesions. Using miRNA (miR) expression signatures as a diagnostic test is expected to improve the FNA diagnosis of thyroid nodules. The aim of this study was to further evaluate the diagnostic value of miRs in thyroid FNA pathology especially of the application of miRs in reclassification of indeterminate/suspicious thyroid FNAs.
Design: Seven miRs (miR-146b, -221, -187, -197, -346, -30d, -138) were selected; the expression levels were measured in archival thyroid FNA specimens.
Results: A set of 4 miRs (miR-146b, -221, -187, -30d) was identified which could differentiate benign from malignant lesions. The differential expression levels of the 4 miRs were analyzed by linear discriminant analysis (LDA), and a 4-miR LDA classifier was obtained to predict FNA specimens as benign or malignant and cross-validated the predictions by comparing with the histological diagnosis. For training sample set (n=60), we obtained diagnostic accuracy of 93.3%, sensitivity of 93.2%, and specificity of 93.8%. For validation sample set (n=42), we obtained diagnostic accuracy of 81.0%, sensitivity of 82.1%, and specificity of 78.6%. FNA cytology classified all the specimens into “indeterminate”, “suspicious”, or “malignant” categories. For the “malignant” FNAs, 45 out 47 (95.7%) were correctly predicted as malignant. For the “indeterminate” FNAs, 29 out of 33 (87.9%) were correctly predicted as benign or malignant. For the “suspicious” cases, 16 out of 22 (72.7%) were correctly predicted as benign or malignant.
Conclusions: Using miR expression profile, most of the thyroid FNA follicular lesions could be predicted as benign or malignant. This method could be potentially developed as a clinical assay in conjunction with FNA cytology to improve the accuracy and confidence of preoperative triage.
Category: Cytopathology

Tuesday, March 1, 2011 11:30 AM

Platform Session: Section F, Tuesday Morning


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