STT3A, C1orf24, TFF3: Putative Markers for Characterization of Follicular Thyroid Neoplasms From Fine‐Needle Aspirates

Abstract

The goals of this study were to characterize gene expression using fine-needle aspirates (FNAs) from follicular neoplasms to distinguish follicular adenomas (FAs) from follicular thyroid carcinomas (FTCs) and follicular variant of papillary thyroid carcinomas (FVPTCs); and to use FNA material to distinguish benign from malignant follicular neoplasms. Retrospective expression analysis of diagnosed follicular neoplasms (level of evidence 2b); prospective cohort of FNA from the operating room after thyroid lobectomy (level of evidence 1b). Gene expression analysis via reverse-transcription polymerase chain reaction (rt-PCR) of nine genes previously noted to be differentially expressed in follicular neoplasms was performed on formalin-fixed, paraffin-embedded archived normal thyroid tissue (n = 63) and follicular neoplasms as diagnosed on preoperative FNA: FA (n = 16), FTC (n = 13), FVPTC (n = 24), and papillary thyroid carcinomas (PTCs) (n = 10). All cases were originally read as follicular neoplasms on preoperative FNA. To determine if these results could be translated into fresh tissue, ex vivo FNA was performed on follicular neoplasms (n = 17) in the operating room after thyroidectomy. Quantitative gene analysis detected differential TFF3 expression in FA versus FTC, FVPTC, and PTC (P = .02). Rt-PCR of FNA samples demonstrated that malignant nodules overexpress STT3A as compared with benign disease (P = .046). The combination of STT3A overexpression/Clorf24 underexpression identified malignant disease (P = .03) on FNA samples. Gene-expression data suggest a difference in expression between STT3A, Clorf24, and TFF3 in FAs versus carcinomas that may be detected from an FNA sample. Findings must be validated from preoperative FNAs in larger numbers.