Fine‐needle aspiration biopsy of thyroid nodules as a possible source for molecular studies: Analysis of RNA obtained from routine cases

Abstract

Thyroid nodules are frequent in clinical practice and fine-needle aspiration biopsy (FNAB) is widely used for its evaluation, but approximately 20% of the cases are diagnosed as indeterminate for malignancy. Aspirates from thyroid nodules can be used for ancillary methods, but molecular techniques are not routinely applied to these specimens. Forty-six consecutive, routinely performed, FNAB of thyroid nodules were evaluated for the feasibility of applying RT-PCR method. RNA was extracted from 1 of 3 fresh residual samples and analyzed to determine its pureness, integrity, and concentration. Cellularity was adequate in all 46, except one, specimens analyzed, scored as 0, 1+, 2+, 3+, and 4+ in 1, 10, 14, 9, and 8 cases, respectively. Thirty-three nodules measured less than 1.5 cm. Cytological diagnosis was positive for malignancy in 3 cases, indeterminate for malignancy in 3, most probably benign follicular lesion in 7, negative for malignancy in 32, and suggestive of benign follicular lesion in 1. Good quality RNA was successfully isolated in 45/46 (97.8%) samples, with an average RNA concentration of 14 ng/microl and detection of B2M mRNA in 97.7% (44/45). There was no significant correlation between RNA concentration and nodule size or specimen cellularity. In conclusion, molecular analysis using individual, residual samples of thyroid nodules aspirates is feasible and could be employed for molecular preoperative studies in the future, adding elements for final cytological diagnosis of indeterminate cases, without altering the routine procedure.

Late Age- and Dose-Related Effects on the Proteome of Thyroid Tissue in Rats after ¹³¹I Exposure

“…Several of the proposed biomarkers have previously been identified in thyroid diseases. Increased beta-2-microglobulin (B2M) expression was seen in thyroid cancer [32][33][34]. Increased enzymatic activity of ADA was seen for thyrotoxicosis, thyroid cancer, adenomas and thyroiditis [35].…”

Late Age- and Dose-Related Effects on the Proteome of Thyroid Tissue in Rats after 131I Exposure

“…Several of the proposed biomarkers have previously been identified in thyroid diseases. Increased beta-2-microglobulin (B2M) expression was seen in thyroid cancer [32][33][34]. Increased enzymatic activity of ADA was seen in thyrotoxicosis, thyroid cancer, adenomas, and thyroiditis [35].…”

Thyroid metastasis from lung adenocarcinoma with EML4-ALK rearrangement

“…Good-quality RNA can be successfully isolated in about 98% of patients with thyroid FNAB. 21 We believe that thyroid FNAB is effective for demonstrating cytology or histology, and metastatic thyroid tumour from ALK-positive lung cancer can be diagnosed accurately by RT-PCR.…”