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: 2.64). 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.

    • "In recent years, the BRAFV600E mutation has emerged as a highly specific diagnostic marker and a useful prognostic factor in the risk stratification of PTC (Xing 2007). Results from many studies have indicated that BRAFV600E mutation is significantly associated with aggressive clinicopathological features of PTC, such as multifocality, extrathyroid extension, lymph node metastases (LNMs) at presentation, and advanced stage (Xing 2007, Mathur et al. 2010, Moses et al. 2010). Recent large meta-analyses of studies on general PTC re-confirmed the association of the BRAFV600E mutation with prognostic factors and poor clinical outcomes of PTCs (Kim et al. 2012, Tufano et al. 2012). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The prognostic value of the BRAFV600E mutation resulting in poor clinical outcomes of papillary thyroid carcinoma have been generally confirmed. However, the association of BRAFV600E with aggressive clinical behaviors of papillary thyroid microcarcinoma (PTMC) has not been firmly established in individual studies. We performed this meta-analysis to examine the relationship between BRAFV600E mutation and the clinicopathological features of PTMC. We conducted a systematic search in PubMed, EMBASE and the Cochrane library for relevant studies. We selected all the studies that reported clinicopathological features of PTMC patients with available information on BRAFV600E mutation status. Nineteen studies consisting of a total of 3,437 patients met these selection criteria and were included for analyses. The average prevalence of the BRAFV600E mutation was 47.48%, with no significant difference with patient sex (male vs female) and age (younger than 45 years vs 45 years or older). Compared with the wild-type BRAF gene, BRAFV600E mutation was associated with tumor multifocality (OR 1.38; 95% CI, 1.04-1.82), extrathyroidal extension (OR 3.09; 95% CI, 2.24-4.26), lymph node metastases (OR 2.43; 95% CI, 1.28-4.60), and advanced stage (OR 2.39; 95% CI, 1.38-4.15) of PTMC. Thus, our findings from this large meta-analysis definitively demonstrate that BRAFV600E mutation-positive PTMC are more likely to manifest with aggressive clinicopathological characteristics. In appropriate clinical settings, testing of BRAFV600E mutation is likely to be useful in assisting the risk stratification and management of PTMC.
    No preview · Article · Jan 2015 · Endocrine Related Cancer
  • Source
    • "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. "
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Jul 2014 · Yonsei Medical Journal
    • "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] "
    [Show abstract] [Hide abstract]
    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.
    No preview · Article · Nov 2013 · CytoJournal
Show more