Investigation of BRAF V600E mutation in papillary thyroid carcinoma and tumor-surrounding nontumoral tissues

Novel RET Proto-oncogene variants identified in Turkish patients with thyroid carcinoma

Thyroid cancer is one of the few malignancies whose incidence is increasing in the last decades. Advances in understanding the molecular mechanisms lead to provide opportunity for prevention, effective early identification and targeted therapies for management. A total of 63 patients with participated in this study Genomic DNA samples were obtained from the samples formalin- embedded tissue and peripheral blood. Following polymerase chain reaction amplification of the 6 RET key exons (10, 11, 13, 14, 15, and 16) were applied and PCR products were subjected to next generation DNA sequencing (ABI 3730). Results revealed that; genotype frequencies were for rs1800961 (G > T) , GG 6 (%9.5), GT 17 (%27) TT40 (%63.5) for rs2472732 (G > A), GG31 (%49.2) GA29 (%46) AA3 (%4.8,) for rs1799939, (G > A) GG42 (%66.7) GA19 (%30.2) AA2 (%3.2), for rs1800962, (C > T) CC54 (%85.7) CT9 (%14.3), for rs1800863 (C > G), CC39 (%61.9) CG22 (%34.9) GG2 (%3.2), for rs3026272 (C > G) CC 13 (%20.6) CG 50 (%79.4). Additionally 15 potential novel genetic variants were identified in these key exons. Detailed information was given both known and new detected variants in supplementary table. Genetic variants distribution frequencies and new variants represented in Turkish thyroid cancer patients for RET proto-oncogene and that results would provide contribution to the literature.

Coexisting Germline CHEK2 and Somatic BRAFV600E Mutations in Papillary Thyroid Cancer and Their Association with Clinicopathological Features and Disease Course

BRAF^V600E is the most common somatic mutation in papillary thyroid carcinoma (PTC) and the majority of evidence indicates that it is associated with an aggressive clinical course. Germline mutations of the CHEK2 gene impair the DNA damage repair process and increase the risk of PTC. Coexistence of both mutations is expected to be associated with poorer clinical course. We evaluated the prevalence of concomitant CHEK2 and BRAF^V600E mutations and their associations with clinicopathological features, treatment response, and disease course in PTC patients. The study included 427 unselected PTC patients (377 women and 50 men) from one center. Relationships among clinicopathological features, mutation status, treatment response, and disease outcomes were assessed. Mean follow-up was 10 years. CHEK2 mutations were detected in 15.2% and BRAF^V600E mutations in 64.2% patients. Neither mutation was present in 31.4% cases and both BRAF^V600E and CHEK2 mutations coexisted in 10.8% patients. No significant differences in clinicopathological features, initial risk, treatment response, or disease outcome were detected among these patient groups. CHEK2 mutations were significantly associated with older age, while BRAF^V600E was significantly associated with older age and extrathyroidal extension. The coexistence of both mutations was not associated with more aggressive clinicopathological features of PTC, poorer treatment response, or disease outcome.

Clinical significance of the BRAFV600E mutation in PTC and its effect on radioiodine therapy

The goal of this study was to explore the relationship of the BRAFV600E mutation with clinicopathologic factors and evaluate the effect of radioactive iodine (RAI) therapy in a large group of intermediate- and high-risk papillary thyroid cancer (PTC) patients with the BRAFV600E mutation and without distant metastases. We collected data for PTC patients who underwent total or near-total thyroidectomy and RAI treatment in our hospital from January 2014-December 2017. There were 1220 PTC patients who met the criteria, and the BRAFV600E mutation was observed in 979 of them (80.2%). Multivariate analysis identified that the BRAFV600E mutation remained independently associated with age at diagnosis, and bilaterality (OR = 1.023, 95% CI = 1.012-1.039, P < 0.001; OR = 1.685, 95% CI = 1.213-2.341, P = 0.002, respectively). In addition, the patients with bilateral PTCs had a higher prevalence of extrathyroid invasion, capsular invasion and fusion of metastatic lymph nodes than the unilateral PTC patients. The response to RAI therapy was evaluated in both the entire series and the patients with a high recurrence risk; no significant difference was discerned between the BRAFV600E mutation and the wild-type groups (P = 0.237 and P = 0.498, respectively). To summarize, our results confirmed that PTC patients with the BRAFV600E mutation exhibit more aggressive characteristics. In addition, the patients with bilateral PTC have a higher incidence of extrathyroid invasion. Moreover, BRAFV600E mutation PTC patients did not show a poorer clinical response after postsurgical RAI therapy, suggesting that RAI therapy may improve the general clinical outcome of these patients.

Detection of BRAF V600E Mutations With Next-Generation Sequencing in Infarcted Thyroid Carcinomas After Fine-Needle Aspiration

OBJECTIVES

Fine-needle aspiration (FNA) of thyroid lesions may result in infarction and diagnostic difficulties on subsequent thyroidectomy specimens. Next-generation sequencing (NGS) methods for detection of hallmark driver BRAF V600E mutations may help characterize such tumors in which histologic alterations preclude definitive tissue diagnosis.

METHODS

Thyroidectomy specimens with both malignant FNA diagnoses and resultant infarction were identified from our institutional database. NGS methods were used to detect BRAF V600E mutations in the infarcted thyroid carcinomas.

RESULTS

Nine thyroid carcinomas with infarction were characterized as BRAF-like papillary thyroid carcinoma based on molecular driver categorization and histologic diagnosis. BRAF V600E mutations were detected in the infarcted tissue in four (67%) of six lesions.

CONCLUSIONS

We demonstrate detection of hallmark BRAF V600E mutations by NGS within infarcted tissue of thyroid carcinomas after FNA. This suggests a potential ancillary method of characterizing infarcted thyroid carcinomas whose altered histology may be nondiagnostic.

Occult Langerhans Cell Histiocytosis Presenting with Papillary Thyroid Carcinoma, a Thickened Pituitary Stalk and Diabetes Insipidus

Etiologies of a thickened stalk include inflammatory, neoplastic, and idiopathic origins, and the underlying diagnosis may remain occult. We report a patient with a thickened pituitary stalk (TPS) and papillary thyroid carcinoma (PTC) whose diagnosis remained obscure until a skin lesion appeared. The patient presented with PTC, status postthyroidectomy, and I¹³¹ therapy. PTC molecular testing revealed BRAF mutant (V600E, GTC>GAG). She had a 5-year history of polyuria/polydipsia. Overnight dehydration study confirmed diabetes insipidus (DI). MRI revealed TPS with loss of the posterior pituitary bright spot. Evaluation showed hypogonadotropic hypogonadism and low IGF-1. Chest X-ray and ACE levels were normal. Radiographs to evaluate for extrapituitary sites of Langerhans Cell Histiocytosis (LCH) were unremarkable. Germinoma studies were negative: normal serum and CSF beta-hCG, alpha-fetoprotein, and CEA. Three years later, the patient developed vulvar labial lesions followed by inguinal region skin lesions, biopsy of which revealed LCH. Reanalysis of thyroid pathology was consistent with concurrent LCH, PTC, and Hashimoto's thyroiditis within the thyroid. This case illustrates that one must be vigilant for extrapituitary manifestations of systemic diseases to diagnose the etiology of TPS. An activating mutation of the protooncogene BRAF is a potential unifying etiology of both PTC and LCH.

BRAF and Epithelial-Mesenchymal Transition: Lessons From Papillary Thyroid Carcinoma and Primary Cutaneous Melanoma

The increased prevalence of BRAF mutations in thyroid carcinoma and primary cutaneous melanoma (PCM) hint that dysregulation of BRAF might contribute to the noted association between PCM and thyroid carcinoma. A recent study evaluating the rate of BRAFV600E mutations among patients who had been diagnosed with primary papillary thyroid carcinoma (PTC) and PCM showed that patients with either PCM or PTC were at an increased risk of developing the other as a second primary malignant neoplasm. Furthermore, the authors noted that samples from patients suffering from both malignancies exhibited a higher rate of incidence of the BRAFV600E mutation, compared with patients not suffering from both malignancies. These studies support the hypothesis that the pathogenesis of these 2 malignancies might share a conserved molecular pattern associated with dysregulation of the BRAF protein. One mechanism through which BRAF might contribute to PCM and thyroid carcinoma progression is through induction of epithelial-mesenchymal transition (EMT). Specifically, the Snail/E-cadherin axis has been demonstrated as a pathway dysregulated by BRAF, leading to EMT in both malignancies. Our analysis focuses on the results of these recent investigations, and through a review of select molecules relevant to EMT, looks to provide a context by which to better understand the relevance and role of stromal-parenchymal signaling and the BRAF mutation in the pathogenesis of PTC and PCM.

Associations of the BRAF (V600E) mutation and p53 protein expression with clinicopathological features of papillary thyroid carcinomas patients

The BRAF (V600E) mutation is the most prevalent type of genetic alteration that has been identified in papillary thyroid carcinoma (PTC); in addition, previous immunohistochemical studies have revealed the overexpression of p53 protein in PTC. The aim of the present study was to investigate the prevalence of the BRAF (V600E) mutation and the expression of p53 in PTC, as well as to determine any associations between these two factors and the clinicopathological features of PTC. The study was performed on 66 PTC patients who underwent surgical tumor resection between January and December 2012. Polymerase chain reaction-based DNA amplification was used to analyze extracted DNA from the tumor specimens in order to determine the prevalence of the BRAF (V600E) mutation. In addition, immunohistochemical analysis was employed in order to evaluate the protein expression of p53 in sections of tumor tissue. Furthermore, statistical analysis was performed in order to determine any associations among the BRAF (V600E) mutation prevalence, p53 overexpression and the clinicopathological features of PTC patients, including age, gender, tumor size, multiplicity, lymph node metastasis and extrathyroidal extension. The results revealed that the BRAF (V600E) mutation was observed in 50 (75.8%) of the 66 PTC patients and overexpression of p53 was found in 52 (78.8%) of 66 cases. No significant correlations were observed between the BRAF (V600E) mutation or p53 protein overexpression and the clinicopathological features of patients. However, the BRAF (V600E) mutation demonstrated noteworthy, but non-significant, correlations with the overexpression of p53 (P=0.0854) and extrathyroidal extension (P=0.0661). In addition, a significant correlation was observed between lymph node metastasis and bilaterality (P=0.0280). In conclusion, the present study demonstrated that the BRAF (V600E) mutation and overexpression of p53 were not significantly correlated with clinicopathological features of PTC, although notable associations were identified between BRAF (V600E) mutation and overexpression of p53 as well as extrathyroidal extension. In addition, lymph node metastasis was significantly associated with bilaterality.

Comparison of the clinicopathological behavior of the follicular variant of papillary thyroid carcinoma and classical papillary thyroid carcinoma: A systematic review and meta-analysis

The follicular variant of papillary thyroid carcinoma (FV-PTC) is the second most common type of papillary thyroid carcinoma (PTC), and it has been increasingly diagnosed in recent years. However, whether FV-PTC behaves differently from classical PTC (C-PTC) remains controversial. To address this controversy, a meta-analysis was performed to determine the potential differences between FV-PTC and C-PTC in their clinicopathological behavior. The relevant published studies between January 1, 2003 and August 31, 2014 were reviewed according to the defined selection criteria using the PubMed database. Review Manager was used to calculate the pooled odds ratio (OR) or the mean difference (MD) with a 95% confidence interval (CI), using a random- or fixed-effect model for all analyses. In total, 112 studies were identified and examined; finally, only 36 studies met the inclusion criteria. In the 36 studies, compared to the clinicopathological behavior of patients with C-PTC, patients with FV-PTC had the following parameters: Similar mean age and similar prevalence of gender, tumor size ≥10 mm, multifocality, capsular invasion, vascular invasion, lymphocytic and/or Hashimoto's thyroiditis, and clinical stage; a larger mean tumor size and higher prevalence of age ≥45 years; and lower prevalence of extrathyroidal extensions, lymph node metastases, BRAF mutation and recurrence. The meta-analysis suggested that patients with FV-PTC have a more favorable clinicopathological behavior and improved prognosis compared to patients with C-PTC. Thus, patients with FV-PTC and C-PTC may be managed differently, and the two types of PTC should be clearly distinguished in future retrospective or prospective studies.

BRAF(V600E) Mutation, RET/PTC1 and PAX8-PPAR Gamma Rearrangements in Follicular Epithelium Derived Thyroid Lesions - Institutional Experience and Literature Review

BACKGROUND

Thyroid cancers are the most frequently occurring endocrine malignancy worldwide. In Turkey, thyroid cancers are ranked 2(nd) on the incidence list in women, with a rate of 16.2%, but they are not included among the top 10 cancer types in men.

AIMS

To identify the contribution of the BRAF(V600E) mutation, and the RET/PTC1 and PAX8-PPARγ rearrangements in the diagnosis and differential diagnosis of follicular epithelial-derived thyroid lesions.

STUDY DESIGN

Retrospective clinical and molecular genetic study.

METHODS

A total of 86 thyroid cases diagnosed between 2001 and 2012 at the Department of Pathology were included in the retrospective study group. Samples best representing the lesion and comprising capsules were chosen in the selection of paraffin blocks pertaining to the cases. The BRAF(V600E) mutation, and the RET/PTC1 and PAX8-PPARγ rearrangements were investigated in all cases.

RESULTS

The BRAF(V600E) mutation was observed in 12 out of 37 papillary carcinoma cases (32.4%), in 1 out of 15 follicular carcinoma cases (6.6%), and in 1 out of 7 undifferentiated carcinoma cases (14.3%). No mutation was detected in benign lesions. The RET/PTC1 rearrangement was detected in 2 out of 7 undifferentiated carcinoma cases (28.6%), and in 1 out of 15 follicular carcinoma cases (6.6%). No gene rearrangement was detected in benign lesions. The PAX8-PPARγ rearrangement was detected in 5 out of 15 follicular thyroid carcinoma cases (33.3%) and in 1 out of 15 follicular adenoma cases (6.6%).

CONCLUSION

The BRAF(V600E) mutation and RET/PTC1 rearrangement were effective in distinguishing the follicular epithelium-derived benign and malignant lesions of the thyroid in the resection materials. The BRAF(V600E) mutation was rather specific to papillary carcinoma in the thyroid, and in cases where the BRAF(V600E) mutation was detected, multi-centricity, lymph node metastasis and capsular invasion findings were observed more frequently compared to cases in which no mutation was observed. The PAX8-PPARγ rearrangement was observed to be more effective in the differentiation of adenomas and carcinomas in follicular neoplasms of the thyroid, whereas the RET/PTC1 analysis contributed to the differential diagnosis of papillary carcinoma histogenesis at a frequency of 29% in undifferentiated thyroid carcinomas.