BRAF mutation in papillary thyroid cancer and its value in tailoring initial treatment: a systematic review and meta-analysis

The BRAF V600E mutation in papillary thyroid cancer with positive or suspected pre-surgical cytological finding is not associated with advanced stages or worse prognosis

The mutation BRAF V600E is thought to be a putative prognostic marker of the aggressiveness of several cancers among which is also papillary thyroid cancer. Our study aimed to evaluate whether this mutation is associated with advanced stages of disease or with a worse prognosis in a series of patients with cytological findings of Thyr 4 and Thyr 5 and who were undergoing total thyroidectomy and routine central compartment lymph-node dissection. 110 patients were consecutively enrolled over an 18-month period from September 2010 to March 2012. All patients had cytological findings that were either indicative of, or positive for papillary thyroid cancer, Thyr 4 or Thyr 5. Detection of BRAF mutation was made on fine-needle aspiration specimen by pyrosequencing after microdissection and DNA extraction of neoplastic cells. After surgical intervention, the patients underwent radioiodine ablation according to our protocol, and follow-up was performed after 8 months. The BRAF V600E mutation was found in 79 % of our cases: 85.7 % of these cases represented the classical variant, 57.8 % the follicular variant, 89.6 % the tall cell variant, and 33.3 % the solid variant. All patients had confirmation of papillary thyroid cancer after histology, with no differences being seen in pTNM presentation between patients with BRAF wild-type and patients with BRAF V600E mutation. Ninety-nine patients underwent radioiodine ablation. Results at follow-up 8 months after radioiodine ablation showed no differences in the rate of ablation between patients harboring BRAF V600E mutation and those having BRAF wild-type. The BRAF V600E mutation doesn't appear to be a reliable risk factor for the aggressiveness of a tumor. BRAF analysis should neither be the only guide for pre-surgical decisions regarding the extent of surgery nor for post-surgical decisions regarding the aggressiveness of the treatment.

Static and dynamic prognostic factors of papillary thyroid carcinoma

The two types of prognostic factors of papillary thyroid carcinoma (PTC) are static and dynamic. The following static prognostic factors have been conventionally adopted: age, tumor size, extrathyroid extension, lymph node metastasis, and distant metastasis based on pre-, intra- and post-operative findings. These factors are useful to decide therapeutic strategies for PTC patients, including the extent of surgery and radioactive iodine (RAI) ablation. However, even the combination of these factors evaluated pathologically postoperatively is not good enough at predicting recurrence in clinical settings. The dynamic prognostic factors of changes in serum thyroglobulin (Tg) and thyroglobulin antibody (TgAb) values in patients who have undergone a total thyroidectomy are important to evaluate the progression of carcinoma recurrence and to predict patients' cause-specific survival, regardless of their backgrounds and the clinicopathological features of their PTC. Dynamic prognostic factors are superior to static prognostic factors in terms of expressing the condition of recurrence on a real-time basis.

Inhibition of type 1 17β-hydroxysteroid dehydrogenase impairs the synthesis of 17β-estradiol in endometriosis lesions

CONTEXT

Endometriosis affects 10% of the women before menopause and has important personal, professional, and societal economic burdens. Because current medical treatments are aimed at reducing the symptoms only, novel therapeutic targets should be identified. Endometriosis is estrogen dependent and in some patients the endometriosis tissue is able to produce estrogens in an autocrine/paracrine manner. In a number of patients, this is the consequence of the high local activity of the 17β-hydroxysteroid-dehydrogenases (17β-HSDs), enzymes able to generate active estrogens from precursors with low activity.

OBJECTIVE

The objective of the study was to identify the 17β-HSD(s) responsible for the high local generation of estrogens in endometriosis and test the possibility to inhibit these enzymes for therapeutic purposes.

DESIGN

The expression of different 17β-HSDs involved in the estrogen metabolism was assessed by real-time PCR in eutopic and ectopic tissue from endometriosis patients (n=14). These biopsies had previously confirmed unbalanced local 17β-HSD activity, which caused high estrogen generation. The possibility to block the synthesis of estrogens by one inhibitor specific for type 1 17β-HSD was assessed by HPLC in tissue lysates from endometriosis tissues (n=27).

RESULTS

In all but one of the patients, a high type 1 17β-HSD level is associated with the unbalanced metabolism of estrogens, leading to higher estrogen synthesis in endometriosis than in the endometrium inside the uterus. Inhibition of type 1 17β-HSD restores to various extents, depending on the patient, the correct metabolism. In 19 of 27 patients analyzed (70%), the 17β-HSD type 1 inhibitor decreased the generation of 17β-estradiol by greater than 85%.

CONCLUSIONS

Inhibition of 17β-HSD type 1 can be a potential future treatment option aimed at restoring the correct metabolic balance of estrogens in endometriosis patients with increased local 17β-HSD type 1 enzyme activity.

Immune response in thyroid cancer: widening the boundaries

The association between thyroid cancer and thyroid inflammation has been repeatedly reported and highly debated in the literature. In fact, both molecular and epidemiological data suggest that these diseases are closely related and this association reinforces that the immune system is important for thyroid cancer progression. Innate immunity is the first line of defensive response. Unlike innate immune responses, adaptive responses are highly specific to the particular antigen that induced them. Both branches of the immune system may interact in antitumor immune response. Major effector cells of the immune system that directly target thyroid cancer cells include dendritic cells, macrophages, polymorphonuclear leukocytes, mast cells, and lymphocytes. A mixture of immune cells may infiltrate thyroid cancer microenvironment and the balance of protumor and antitumor activity of these cells may be associated with prognosis. Herein, we describe some evidences that immune response may be important for thyroid cancer progression and may help us identify more aggressive tumors, sparing the vast majority of patients from costly unnecessary invasive procedures. The future trend in thyroid cancer is an individualized therapy.

[Targeted therapies, prognostic and predictive factors in endocrine oncology]

A better understanding of molecular mechanisms responsible for tumorigenesis has allowed the development of targeted drugs designed to improve the outcome of cancer. In endocrine tumors, several molecules have demonstrated efficacy in terms of progression free survival during phase III trials such as vandetanib and cabozantinib in medullary thyroid carcinoma, sorafenib in differentiated thyroid carcinoma and everolimus or sunitinib for pancreatic neuroendocrine tumors. Rare cancer network has allowed ongoing phase III trials in malignant pheochromocytoma and adrenocortical carcinoma. However, to date no specific predictive biomarker has yet been identified for a personalized cancer medicine. We review recent advances in endocrine oncology concerning molecular targets identification, targeted therapies and predictive or prognostic markers.

Prognostic value of the BRAF V600E mutation in papillary thyroid carcinoma

The aim of the present study was to investigate the prevalence of the BRAF V600E mutation in papillary thyroid carcinoma (PTC) and to determine the correlation between this mutation and indicators of poor prognosis and outcome in patients with PTC. The BRAF V600E mutation status was analyzed in 187 tumor samples using the multiplex allele-specific PCR method. Univariate and multivariate analyses were performed to investigate the association of the BRAF V600E mutation with clinical features and patient outcome. The sensitivity of the multiplex allele-specific PCR combined with denaturing high-performance liquid chromatography reached ~1%. The BRAF V600E mutation was observed in 63.6% (119/187) of tumor tissues, predominantly in PTC specimens, and no BRAF mutation was identified in other benign-type thyroid diseases. The univariate analysis indicated that the BRAF V600E mutation was associated with age, tumor stage and prognosis (P<0.05). In addition, the frequency of the BRAF V600E mutation was significantly different in the central (75.3%) and lateral neck (49.3%) lymph nodes of patients with lymph node metastasis. Multivariate logistic regression analysis showed that the BRAF V600E mutation (HR, 2.471; 95% CI, 1.149–5.312) and lymph node metastasis (HR, 3.003; 95% CI, 1.027–8.771) are independent factors that predict tumor prognosis. Thus, the BRAF V600E mutation is an independent risk factor that may be used to predict thyroid cancer persistence/recurrence.

Molecular genotyping of follicular variant of papillary thyroid carcinoma correlates with diagnostic category of fine-needle aspiration cytology: values of RAS mutation testing

BACKGROUND

The follicular variant of papillary thyroid carcinoma (FVPTC) presents distinct histologic subtypes and molecular genotyping. The preoperative diagnosis of FVPTC through fine-needle aspiration cytology (FNAC) is challenging.

METHODS

We reviewed 59 archival thyroid FNAC specimens of surgically confirmed FVPTC according to histologic subtype: encapsulated FVPTC (n = 30) and infiltrative FVPTC (n = 29). Galectin-3 immunostaining and molecular analyses for BRAF and three RAS genes (NRAS, HRAS, and KRAS) were performed.

RESULTS

FNAC diagnoses of FVPTC included benign (5%), atypia of undetermined significance (19%), follicular neoplasm/suspicious for follicular neoplasm (14%), suspicious for PTC (29%), and PTC (34%). Galectin-3 immunostaining was positive in 50% of FNAC specimens. A BRAF mutation was found only in 14 (24%) tumors with the FNAC diagnosis of PTC or suspicious for PTC: 13 cases with the usual c.1799T>A (p.V600E) mutation and 1 case with a 3 base-pair deletion (c.1799_1801delTGA), resulting in a deletion of lysine at codon 601 and a deletion c.1799_1801delTGA that results in a valine-to-glutamate substitution at codon 600 (p.V600_K601>E) while preserving the reading frame. A BRAF K601E mutation was not found. RAS mutations were observed in 18 (33%) tumors (NRAS, 22%; HRAS, 6%; KRAS, 6%). Mutations of the three RAS genes were detected in codon 61 but not in codons 12 and 13. There was a decreasing trend of RAS mutation rates associated with an increasing risk of malignancy in the FNAC diagnostic categories. The triage efficacy of FNAC to make a recommendation for surgery was 73% for encapsulated tumors and 79% for infiltrative tumors. Addition of galectin-3 or the BRAF test to FNAC showed no significant improvement in the triage efficacy. However, RAS mutations significantly improved the triage efficacy of FNAC. There was no significant difference in the triage efficacy of FNAC, galectin-3 expression, and the prevalence of somatic mutations between encapsulated and infiltrative tumors.

CONCLUSION

Thyroid FNAC has a low sensitivity for the detection of FVPTC regardless of histologic subtype. Encapsulated FVPTC and infiltrative FVPTC have similar molecular profiles and rates of galectin-3 expression. RAS mutational analysis is more useful than BRAF testing to improve the triage efficacy of FNAC for FVPTC.

Clinicopathologic implications of the BRAF(V600E) mutation in papillary thyroid cancer: a subgroup analysis of 3130 cases in a single center

BACKGROUND

The BRAF mutation has been shown to be associated with aggressive clinicopathologic characteristics of papillary thyroid cancer (PTC). However, several studies that analyzed hundreds of patients have not demonstrated any correlation. The objective of this study was to investigate the relationship of the BRAF mutation with clinicopathologic factors in a large group of homogenous PTC patients.

METHODS

We collected data of PTC patients who received curative resection of the thyroid gland and who had undergone BRAF mutation tests of their thyroid cancer tissue. Minor variant PTCs and mixed-type thyroid cancers were excluded in this analysis. Clinicopathologic characteristics, including age, sex, BRAF mutation, tumor histology, size, extrathyroidal extension, tumor margin, lymph node metastasis, multifocality, stage, and associated thyroid disease, were collected. The relationship of the BRAF mutation with clinicopathologic factors was analyzed in each homogenous histologic PTC.

RESULTS

There were 3130 PTC patients who met the criteria, and these patients were divided into three major histologic groups: conventional PTC (n = 2947), diffuse sclerosing variant PTC (n = 98), and follicular variant PTC (n = 85). The BRAF mutation was variably detected in 75.3%, 61%, and 40% of patients, respectively. In conventional PTC cases, the BRAF mutation was significantly associated with large tumor size, extrathyroidal extension, and lymph node metastasis. Coexistent chronic lymphocytic thyroiditis was significantly less prevalent in the BRAF mutant group. Age, sex, and tumor margin status were not significantly correlated with the BRAF status. There was no evidence that any clinicopathologic factors were linked with the BRAF mutation status in diffuse sclerosing and follicular variant PTCs.

CONCLUSIONS

The BRAF mutation was differentially detected in each histologic subtype of PTC and was strongly correlated with pathologic factors, most strongly with no coexistent chronic lymphocytic thyroiditis, in conventional PTC. The BRAF mutation is suggested to be a poor prognostic marker in conventional PTC, and the BRAF mutational analysis may lead to better management for individual PTC patients.

Inferring primary tumor sites from mutation spectra: a meta-analysis of histology-specific aberrations in cancer-derived cell lines

Next-generation sequencing technologies have led to profound characterization of mutation spectra for several cancer types. Hence, we sought to systematically compare genomic aberrations between primary tumors and cancer lines. For this, we compiled publically available sequencing data of 1651 genes across 905 cell lines. We used them to characterize 23 distinct primary tumor sites by a novel approach that is based on Bayesian spam-filtering techniques. Thereby, we confirmed the strong overall similarity of alterations between patient samples and cell culture. However, we also identified several suspicious mutations, which had not been associated with their cancer types before. Based on these characterizations, we developed the inferring cancer origins from mutation spectra (ICOMS) tool. On our cell line collection, the algorithm reached a prediction specificity rate of 79%, which strongly variegated between primary cancer sites. On an independent validation cohort of 431 primary tumor samples, we observed a similar accuracy of 71%. Additionally, we found that ICOMS could be employed to deduce further attributes from mutation spectra, including sub-histology and compound sensitivity. Thus, thorough classification of site-specific mutation spectra for cell lines may decipher further genome-phenotype associations in cancer.

Translational research in endocrine surgery

This article reviews translational research in endocrine surgery, with a focus on disorders of the thyroid, parathyroids, adrenals, and endocrine pancreas. Discovery of genes responsible for heritable endocrine cancer syndromes has increased knowledge of the causes and mechanisms of endocrine cancer and has refined surgical treatment options. Knowledge of mutations in sporadic cancer has led to rapid progress in small-molecule kinase inhibitor strategies. These breakthroughs and their influence on current therapy are discussed to provide surgeons with an overview of the basic science research currently creating new clinical treatments and improving patient care.

Shifted termination assay (STA) fragment analysis to detect BRAF V600 mutations in papillary thyroid carcinomas

Background

BRAF mutation is an important diagnostic and prognostic marker in patients with papillary thyroid carcinoma (PTC). To be applicable in clinical laboratories with limited equipment, diverse testing methods are required to detect BRAF mutation.

Methods

A shifted termination assay (STA) fragment analysis was used to detect common V600 BRAF mutations in 159 PTCs with DNAs extracted from formalin-fixed paraffin-embedded tumor tissue. The results of STA fragment analysis were compared to those of direct sequencing. Serial dilutions of BRAF mutant cell line (SNU-790) were used to calculate limit of detection (LOD).

Results

BRAF mutations were detected in 119 (74.8%) PTCs by STA fragment analysis. In direct sequencing, BRAF mutations were observed in 118 (74.2%) cases. The results of STA fragment analysis had high correlation with those of direct sequencing (p < 0.00001, κ = 0.98). The LOD of STA fragment analysis and direct sequencing was 6% and 12.5%, respectively. In PTCs with pT3/T4 stages, BRAF mutation was observed in 83.8% of cases. In pT1/T2 carcinomas, BRAF mutation was detected in 65.9% and this difference was statistically significant (p = 0.007). Moreover, BRAF mutation was more frequent in PTCs with extrathyroidal invasion than tumors without extrathyroidal invasion (84.7% versus 62.2%, p = 0.001). To prepare and run the reactions, direct sequencing required 450 minutes while STA fragment analysis needed 290 minutes.

Conclusions

STA fragment analysis is a simple and sensitive method to detect BRAF V600 mutations in formalin-fixed paraffin-embedded clinical samples.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5684057089135749

Detection and management of cervical lymph nodes in papillary thyroid cancer

Lymph node metastases in papillary thyroid cancer are a common occurrence; however, the management of clinically negative cervical lymph nodes remains controversial. Preoperative neck ultrasound mapping is crucial, and complete dissection of a nodal compartment is recommended for any metastatic lymph nodes. The role of prophylactic central neck dissection remains controversial. The BRAF V600E mutation is a common mutation in papillary thyroid cancer, and has been associated with more aggressive tumor behavior. Evaluating the BRAF status of tumors may have implications for treatment and surveillance. New areas of research continue to focus on risk stratification and identifying which patients benefit from a more aggressive treatment, such as prophylactic central lymphadenectomy and radioiodine ablation and more intense surveillance strategies.

Rapid detection of K-, N-, H-RAS, and BRAF hotspot mutations in thyroid cancer using the multiplex primer extension

OBJECTIVES

The objective of this study is to develop a multiplex PCR and primer extension to detect K-, N-, H-RAS, and BRAF mutations.

DESIGN AND METHODS

DNA samples were isolated from 76 thyroid cancer patients. Multiplex amplification of exons 2 and 3 of three RAS genes and exon 15 of the BRAF gene using three pairs of primers was performed in a single tube. The products were split into three tubes. First, we used nine different-sized N-RAS and BRAF primers to detect base changes in N-RAS and BRAF. The other two tubes used seven separate different-sized K-RAS and H-RAS primers to detect base changes.

RESULTS

We compared these results with direct sequencing. The two methods generated identical results, but our method was superior to direct sequencing in terms of the amount of work and time involved.

CONCLUSIONS

We present a rapid method to detect mutations of K-, N-, H-RAS, and BRAF in human cancers.

Expressions of miRNAs in papillary thyroid carcinoma and their associations with the BRAFV600E mutation

OBJECTIVE

Alterations in microRNA (miRNA) expression have been described in thyroid tumors, suggesting a role for miRNAs in thyroid carcinogenesis. BRAF(V600E) is the most frequently identified genetic alteration in papillary thyroid carcinoma (PTC). We investigated the link between BRAF(V600E) status and the expression of miRNAs in PTC and analyzed the associations of these factors with clinicopathological characteristics.

DESIGN AND METHODS

Prospective study of patients who underwent thyroid surgery between October 8, 2008 and November 1, 2010. BRAF(V600E) status was determined by mutant allele-specific amplification PCR and direct sequencing of exon 15 of the BRAF gene in 69 PTC tissues and 69 respective paracancerous normal thyroid tissues. Initially, miRNA expression was analyzed in 12 PTC tissues and three associated paracancerous tissues using a miRNA microarray. miRNAs differentially expressed between BRAF(V600E)-positive and -negative PTC tissues were then validated by real-time quantitative PCR on 69 PTC tissues and 69 paracancerous tissues. We also explored the associations between BRAF(V600E) status or differential miRNA expression and clinicopathological characteristics.

RESULTS

The mutation rate of BRAF(V600E) in PTC was 47.8%. Twelve miRNAs were upregulated and six were downregulated in PTC tissues, among which miR-15a, 15a*, 34a*, 34b*, 551b, 873, 876-3p, and 1274a were first identified. miR-21* and 203 were significantly dysregulated (P<0.05) in PTC tissues with BRAF(V600E). Additionally, there were significant associations (P<0.05) between BRAF(V600E) and a higher tumor-node-metastasis staging (III/IV), and between miR-21* over-expression and lymph node metastasis.

CONCLUSIONS

We identified two miRNAs that are differentially expressed in PTC tissues with BRAF(V600E) and revealed their associations with clinicopathological features. These findings may lead to the development of a potential diagnostic biomarker or prognostic indicator of PTC.

Clinical Significance of BRAF Mutation in Thyroid Papillary Cancer

Objective

To correlate the presence of BRAF V600E mutation with clinicopathological parameters.

Study Design

Case-control study.

Setting

BRAF mutation represents the most common oncogenic event in sporadic papillary thyroid cancer (PTC). There are, however, significant discrepancies regarding the overall frequency and its relationship with clinicopathological parameters of poor outcome. We analyzed BRAF mutation in a cohort of patients affected by PTCs to identify its association with clinical variables.

Subjects and Methods

We analyzed retrospectively a series of 304 patients, treated for PTC from 1999 to 2011 at Bologna University Hospital. We searched BRAF mutation by reverse transcription polymerase chain reaction (PCR) followed by PCR and direct sequencing.

Results

BRAF mutation was found in 77.4% of classical PTCs, 31.9% of the follicular variant, and 72.2% of high tall cell PTCs, being significantly associated, at univariate analysis, with recurrence, stage, multicentricity, histologic subtype, extrathyroidal extension, nodule dimension, body mass index, and American Thyroid Association (ATA) risk stratification. Furthermore, higher T, but not N or M, stage was associated with BRAF mutation. In the multivariate analysis, the BRAF mutation was significantly associated only with the ATA risk stratification, in turn showing a significant negative association with recurrence-free survival time with Cox multivariate analysis.

Conclusion

Our results indicate that BRAF mutation identifies a subset of PTC with increased risk of recurrence. The presence of BRAF mutation might be a valuable diagnostic and prognostic marker of the disease. To confirm the diagnostic usefulness of this marker, further studies should be carried out.

Impact of lymph node metastases identified on central neck dissection (CND) on the recurrence of papillary thyroid cancer: potential role of BRAFV600E mutation in defining CND

The impact of metastasized cervical lymph nodes (CLN) identified on central neck dissection (CND) on the recurrence/persistence of papillary thyroid cancer (PTC) and the extent of CND needed to reduce recurrence/persistence have not been firmly established. To assess the impact of CLN metastasis and BRAF mutation on the recurrence/persistence of PTC and the potential of BRAF mutation in assisting CND. Analyses of 379 consecutive patients with PTC who underwent thyroidectomy with (n=243) or without CND (n=136) at a tertiary-care academic hospital during the period 2001-2010 for their clinicopathological outcomes and BRAF mutation status. Increasingly aggressive tumor characteristics were found as the extent of CND was advanced following conventional risk criteria from non-CND to limited CND to formal CND. Disease recurrence/persistence rate also sharply rose from 4.7% to 15.7% and 40.5% in these CND settings respectively (P<0.0001). CLN metastasis rate rose from 18.0 to 77.3% from limited CND to formal CND (P<0.0001). An increasing rate of BRAF mutation was also found from less to more extensive CND. A strong association of CLN metastasis and BRAF mutation with disease recurrence/persistence was revealed on Kaplan-Meier analysis and BRAF mutation strongly predicted CLN metastasis. CLN metastases found on CND are closely associated with disease recurrence/persistence of PTC, which are both strongly predicted by BRAF mutation. Current selection of PTC patients for CND is appropriate but higher extent of the procedure, once selected, is needed to reduce disease recurrence, which may be defined by combination use of preoperative BRAF mutation testing and conventional risk factors of PTC.