Article

Molecular Testing for Somatic Mutations Improves the Accuracy of Thyroid Fine-needle Aspiration Biopsy

Department of Surgery, University of California, San Francisco, CA 94143, USA.
World Journal of Surgery (Impact Factor: 2.35). 11/2010; 34(11):2589-94. DOI: 10.1007/s00268-010-0720-0
Source: PubMed

ABSTRACT Thyroid fine-needle aspiration (FNA) biopsy is indeterminate or suspicious in up to 30% of cases and these patients are commonly subjected to at least a diagnostic hemithyroidectomy. If malignant on histology, a completion thyroidectomy is usually performed, which may be associated with higher morbidity. To determine the clinical utility of genetic testing in thyroid FNA biopsy, we conducted a prospective clinical trial.
Four hundred seventeen patients with 455 thyroid nodules were enrolled and had genetic testing for common somatic mutations (BRAF, NRAS, KRAS) and gene rearrangements (RET/PTC1, RET/PTC3, RAS, TRK1) by PCR and direct sequencing and by nested PCR, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of genetic testing in thyroid FNA biopsy were determined based on the histologic diagnosis.
One hundred twenty-five of 455 thyroid nodule FNA biopsies were indeterminate or suspicious on cytologic examination. Overall, 50 mutations were identified (23 BRAF, 4 RET/PTC1, 2 RET/PTC3, 21 NRAS) in the thyroid FNA biopsies. There were significantly more mutations detected in malignant thyroid nodules than in benign (P = 0.0001). For thyroid FNA biopsies that were indeterminate or suspicious, genetic testing had a sensitivity of 12%, specificity of 98%, PPV of 38%, and NPV of 65%.
Genetic testing for somatic mutations in thyroid FNA biopsy samples is feasible and identifies a subset of malignant thyroid neoplasms that are indeterminate or suspicious on FNA biopsy. Genetic testing for common somatic genetic alterations thus could allow for more definitive initial thyroidectomy in those with positive results.

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    • "To resolve this issue, the scientific community has struggled to translate molecular markers into useful clinical tools for patients with thyroid nodules, and nowadays, several molecular markers are used to improve diagnostic accuracy in cases with inconclusive cytological results.4,5 Mutations or aberrant expressions of genes coding for signaling cascade proteins (RET, RAS, BRAF, PI3K, PTEN, AKT) have been identified in the majority of papillary thyroid carcinoma (PTC) patients.18,19,20 These alterations change the MAPK/ERK pathway and PI3K/Akt pathway, which play important roles in the transmission of cell signals and contribute to the transformation of malignant follicular cells. "
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    ABSTRACT: Purpose We investigated the merit of ultrasound (US) features and BRAFV600E mutation as an additional study of cytology and compared the diagnostic performances of cytology alone, cytology with US correlation, cytology with BRAFV600E mutation, and a combination of cytology, US, and BRAFV600E mutation all together. Materials and Methods This study included 185 patients (mean age, 48.4 years; range 20-77 years) with 191 thyroid nodules who underwent US-guided fine-needle aspiration (FNA) with an additional BRAFV600E mutation test. Three radiologists highly experienced in thyroid imaging retrospectively reviewed US images and classified each nodule into two categories (positive for malignancy or negative for malignancy). Interobserver variability (IOV) of US assessment between the three readers was estimated using the generalized kappa statistic of Landis and Koch. We also calculated the diagnostic performances of these studies. Results There were 131 cases of malignancy (131/191, 68.6%) and 60 cases of benign nodules (60/191, 31.4%). In terms of IOV of US assessment, the generalized kappa value was 0.242, indicating fair agreement was reached. The combination of cytology with BRAFV600E showed higher specificity (100%) and positive predictive value (PPV) (100%) compared to the combination of cytology, BRAFV600E, and US (specificity 28.3%, 66.7%, 68.3%; PPV 74.6%, 86.6%, 86.8%, respectively; p<0.001). However, cytology with BRAFV600E showed lower sensitivity (84.7%) than cytology with BRAFV600E and US (96.2%, 98.5%, 95.4%, respectively; p<0.001). Conclusion Considering the diagnostic performance and low reproducibility of US, the combination of FNA with BRAFV600E is the most reliable and objective method for diagnosing thyroid malignancy.
    Yonsei Medical Journal 07/2014; 55(4):871-8. DOI:10.3349/ymj.2014.55.4.871 · 1.26 Impact Factor
    • "The latter, mainly defined by the molecular analysis on cytology, is still a challenge demanding an increase in standardization and optimization of pre-analytical and analytical requirements. Numerous papers highlighted the use of molecular testing on cytology, but very scant literature is available on the pre-analytical requirements used for its cytological application.[456789101112] "
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    ABSTRACT: Fine-needle aspiration cytology (FNAC) represents a valid alternative to biopsy in a variety of clinical settings mainly based on its simplicity and less invasive clinical approach. In some cases, morphology evaluation alone is not sufficient to manage the patients, so that the application of ancillary techniques can contribute to diagnosis, prognosis and prediction of tumor behavior. These techniques include polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH), in situ PCR, direct Sequencing, microarrays and proteomic methodologies. Although several recent experiences underline the superior value of deoxyribonucleic acid (DNA) quality mainly for advanced genomic high throughput platforms, very scant literature studied the role of the pre-analytical or analytical phases. Despite the high specificity of molecular techniques as a support for diagnosis, there is a need for an increased standardization of pre-analytical/analytical steps such as providing appropriate clinical history, proper collection of laboratory specimens and proper preparation of samples, adequate fixative/reagent concentrations and technical equipments. All these requirements are crucial according to the results from 42 American laboratories, which reported 0.33% of significant molecular errors with 60% of them in the pre-analytical phase. The most common error is to forget that cytological preparation requires specific molecular variables, which are different from histological specimens. Cytological samples offer the advantage of a well preserved DNA, readily extractable and reasonably stable (from 6 months to 5 years) avoiding pitfalls due to formalin-fixation. Freshly prepared, unstained direct, alcohol-fixed papanicolaou, air-dried diff-quick smears are all suitable for DNA extraction and preservation. In the specific field of thyroid FNAC, molecular analysis has been supported by the growing evidence that papillary thyroid carcinoma (PTC), the most common thyroid cancer, frequently is a diploid lesion and can display non-overlapping mutations of the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) in 46% to 70%, cases, ret proto-oncogene (RET) in 3 to 85% and Rat Sarcoma oncogene (RAS) in 0-21% cases. Recently, several cytological papers demonstrated that the combination of morphology and molecular analysis can increase the diagnostic accuracy allowing more precise prediction of malignancy regardless of the diagnostic categories. In conclusion, the correct use of the pre-analytical-analytical steps might lead to optimal results on cytology and empower the prognostic value of molecular techniques as strong indicators of cancer for their high specificity and positive predictive value.
    CytoJournal 11/2013; 10(1):24. DOI:10.4103/1742-6413.122300
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    • "The expansion of knowledge regarding genetic mutations in thyroid cancers has led to the use of molecular markers as an indicator of prognosis and for the malignancy diagnosis especially in indeterminate FNA samples (BRAF, RAS, RET/PTC, and PAX8/PPARγ) [2]. Recent large prospective studies have emphasized the ability of genetic markers (BRAF, RAS, RET/PTC, and PAX8/PPARγ) and protein markers (galectin-3) to significantly improve and affect the preoperative diagnostic accuracy especially for patients who have indeterminate thyroid nodules [30–34]. Moreover, the use of such molecular markers was further recommended by the 2009 revised ATA guidelines where the sensitivity of malignant diagnosis in FNA thyroid nodules was found to be increased from 44% to 80%, when comparing cytology alone to cytology combined with molecular testing for the markers in most of those studies. "
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    ABSTRACT: Thyroid cancer is among the most common endocrine malignancies. Genetic and environmental factors play an important role in the pathogenesis of differentiated thyroid cancer. Both have good prognosis but with frequent recurrences. Cancer staging is an essential prognostic part of cancer management. There are multiple controversies in the management and followup of differentiated thyroid cancer. Debate still exists with regard to the optimal surgical approach but trends toward a more conservative approach, such as lobectomy, are being more favored, especially in papillary thyroid cancer, of tumor sizes less than 4 cm, in the absence of other high-risk suggestive features. Survival of patients with well-differentiated thyroid cancer was adversely affected by lymph node metastases. Prophylactic central LN dissection did improve accuracy in staging and decrease postop TG level, but it had no effect on small-sized tumors. Conservative approach was more applied with regard to the need and dose of radioiodine given postoperatively. There have been several advancements in the management of radioiodine resistant advanced differentiated thyroid cancers. Appropriate followup is required based on risk stratification of patients postoperatively. Many studies are still ongoing in order to reach the optimal management and followup of differentiated thyroid cancer.
    12/2012; 2012:512401. DOI:10.1155/2012/512401
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