Long-Term Outcomes of Parathyroidectomy in Hyperparathyroidism-Jaw Tumor Syndrome: Analysis of Five Families with CDC73 Mutations.

BACKGROUND: Hyperparathyroidism-jaw tumor syndrome (HPT-JT) is a rare disease caused by CDC73 germline mutations, with familial primary hyperparathyroidism (pHPT), ossifying jaw tumors, genito-urinary neoplasms. The present study was aimed at determining the long-term postoperative outcome of parathyroidectomy in HPT-JT. METHODS: A retrospective analysis of a single-center series of 20 patients from five unrelated HPT-JT families undergoing parathyroid surgery was performed. RESULTS: Pathology confirmed a single-gland involvement in 95% of cases at onset. Parathyroid carcinoma occurred in three patients undergoing en-bloc parathyroidectomy and thyroid lobectomy: parathyroid benign lesions in 17 patients undergoing subtotal parathyroidectomy for evident multiglandular involvement (n = 1) or selective parathyroidectomy for single-gland involvement (n = 16), during bilateral (n = 13) or targeted unilateral neck exploration (n = 7). At a median overall follow-up of 16 years (range 2.5-42), patients with parathyroid carcinoma had a persistent/recurrent disease in 66.6%; patients with benign lesions had recurrent pHPT in 23.5% after a prolonged disease-free period; recurrent benign pHPT occurred slightly more often in cases of discordant preoperative localization (60% vs 9%; p = 0.06). CONCLUSION: pHPT in HPT-JT is generally characterized by a benign and single-gland involvement, with a relatively increased risk of malignancy (15%). Parathyroid carcinoma needs extensive surgery because of high risk of permanent/recurrent disease (66.6%). In benign involvement, targeted unilateral exploration with selective parathyroidectomy may be effective in cases of concordant single-gland localization at preoperative localization imaging techniques. Bilateral neck exploration with subtotal parathyroidectomy might be preferred in cases of negative or discordant preoperative localization, because of the increased risk of multiglandular involvement and long-term recurrences (23.5%).

Comparison of the diagnostic accuracy of combined elastosonography and BRAF analysis vs cytology and ultrasonography for thyroid nodule suspected of malignancy.

OBJECTIVE: Diagnosing thyroid nodules preoperatively using traditional diagnostic tools - ultrasonography (US) and cytology - still carries a considerable degree of uncertainty, and surgery is recommended for a far from negligible number of patients simply for diagnostic purposes. Thyroid elastosonography (USE) and BRAF analysis have recently proved useful in detecting thyroid malignancies. The aim of this study is to establish whether combining USE and BRAF testing ameliorates preoperative diagnosis of thyroid nodule candidates for intervention by conventional approaches, thereby avoiding the need for diagnostic surgical procedures. DESIGN AND PATIENTS: We retrospectively analysed the files of 155 consecutive patients with 164 nodules, all assessed by ultrasonography, cytology, USE and BRAF testing, who underwent thyroid surgery. RESULTS: Of the 164 nodules, 74 (45%) were benign and 90 (55%) were malignant at final histology. Combining ultrasonography and cytology identified 21 (13%) as benign, 93 (57%) as malignant or probably malignant and 50 (30%) as 'suspended' (when the combined test was not able to classify the node as benign or malignant) with a 99% sensitivity, 28% specificity, 63% PPV, 95% NPV and 67% accuracy. Combining USE and BRAF testing indicated that 59 (36%) were benign, 74 (45%) were malignant and 31 (19%) were in a 'suspended' category, with a 95% sensitivity, 74% specificity, 82% PPV, 93% NPV and 86% accuracy. CONCLUSIONS: In assessing thyroid nodules suspected of malignancy, the combined analysis of USE and BRAF is equally sensitive and more specific than conventional procedures, achieving more accurate preoperative diagnoses than US and cytology combined. USE and BRAF analysis for thyroid nodule evaluation might reduce the number of unnecessary surgical procedures.

Prognostic significance of TERT promoter and BRAF mutations in TIR-4 and TIR-5 thyroid cytology.

OBJECTIVE: Follicular-derived thyroid cancers generally have a good prognosis, but in a minority of cases, they have an aggressive behavior and develop distant metastases, with an increase in the associated mortality. None of the prognostic markers currently available prior to surgery can identify such cases. METHODS: TERT promoter and BRAF gene mutations were examined in a series of 436 consecutive TIR-4 and TIR-5 nodes referred for surgery. Follow-up (median: 59 months, range: 7-293 months) was available for 384/423 patients with malignant nodes. RESULTS: TERT promoter and BRAF mutations were detected in 20/436 (4.6%) and 257/434 thyroid nodules (59.2%), respectively. At the end of the follow-up, 318/384 patients (82.8%) had an excellent outcome, 48/384 (12.5%) had indeterminate response or biochemical persistence, 18/384 (4.7%) had a structural persistence or died from thyroid cancer. TERT promoter mutations correlated with older age (P < 0.0001), larger tumor size (P = 0.0002), oxyntic and aggressive PTC variants (P = 0.01), higher tumor stages (P < 0.0001), distant metastases (<0.0001) and disease outcome (P < 0.0001). At multivariate analysis, TERT promoter mutation was not an independent predictor of disease outcome. TERT promoter mutation- (OR: 40.58; 95% CI: 3.06-539.04), and N1b lymph node metastases (OR: 40.16, 95% CI: 3.48-463.04) were independent predictors of distant metastases. BRAF mutation did not predict the outcome, and it correlated with a lower incidence of distant metastases (P = 0.0201). CONCLUSIONS: TERT promoter mutation proved an independent predictor of distant metastases, giving clinicians the chance to identify many of the patients who warranted more aggressive initial treatment and closer follow-up.

EF24 (a Curcumin Analog) and ZSTK474 Emphasize the Effect of Cabozantinib in Medullary Thyroid Cancer.

XL184 is a small-molecule kinase inhibitor recently included in first-line systemic therapy for patients with advanced, progressive medullary thyroid cancer (MTC). EF24 is a curcumin analog with a high bioavailability, and ZSTK474 is an inhibitor of the phosphatidylinositol 3-kinase signaling pathway. We investigated the effect of these compounds, alone and in combination, in two rearranged during transfection (RET)-mutated TT and MZ-CRC-1 MTC cell lines and in six mostly RET wild-type human MTC primary cultures. Low IC50 values demonstrated the efficacy of the drugs, whereas the combination index revealed an important synergistic effect of combinations of XL184 + ZSTK474 and XL184 + EF24. Cell-cycle changes and the induction of apoptosis or necrosis were modulated by single compounds or combinations thereof. Both XL184 and EF24, alone or combined, were effective in reducing calcitonin secretion. Western blot and in-cell Western analysis showed that the compounds prompted a decrease in general reactivity to phosphorylated antibodies. Our data confirm XL184 alone as the reference drug for RET-mutated MTC, but we also demonstrated that EF24 alone is effective in inhibiting MTC cell viability. We tested the combinations XL184 + ZSTK474 and XL184 + EF24 too, finding that they act synergistically, irrespective of RET mutation status.

Frequency and Significance of Ras, Tert Promoter, and Braf Mutations in Cytologically Indeterminate Thyroid Nodules: A Monocentric Case Series at a Tertiary-Level Endocrinology Unit.

PURPOSE: The management of thyroid nodules of indeterminate cytology is controversial. Our study aimed to establish the frequency and significance of H-,K-,N-RAS, TERT promoter, and BRAF gene mutations in thyroid nodes of indeterminate cytology and to assess their potential usefulness in clinical practice. METHODS: H-,K-,N-RAS, TERT promoter and BRAF gene mutations were examined in a series of 199 consecutive nodes of indeterminate cytology referred for surgical excision. RESULTS: 69/199 (35%) were malignant on histopathological review. RAS mutations were detected in 36/199 (18%), and 19/36 cases (53%) were malignant on histological diagnosis. TERT promoter mutations were detected in 7/199 (4%) nodules, which were all malignant lesions. BRAF mutations were detected in 15/199 (8%), and a BRAF K601E mutation was identified in 2 follicular adenomas and 1 noninvasive follicular thyroid neoplasm with papillary-like nuclear features. Altogether, this panel was able to identify 48% of the malignant lesions, achieving a specificity, positive predictive value, and negative predictive value for malignancy of 85, 62, and 75%, respectively. CONCLUSION: The residual malignancy risk in mutation-negative nodes is 25%. These nodes still need to be resected, but mutation analysis could help to orient the appropriate surgical strategy.

Prevalence, tumorigenic role, and biochemical implications of rare BRAF alterations.

BACKGROUND: Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland, accounting for 74-80% of all thyroid cancers. The 1799T>A transversion is an activating mutation of the BRAF oncogene that is common in and specific to conventional PTC. We studied the prevalence, tumorigenic role, and biochemical implications of rare BRAF variants in a large cohort of patients. METHODS: A total of 2131 fine-needle aspiration biopsy samples were collected and subjected to BRAF mutation analysis. BRAF genetic variants were analyzed by Western blot, immunofluorescence, and in silico analysis. RESULTS: BRAF mutations were found in 50% (347/700) of thyroid cancers (644 PTCs, 22 anaplastic thyroid carcinomas, 34 follicular thyroid carcinomas). They were the classic (c.1799T>A, p.V600E) mutation in 96.8% (336/347) and rare genetic variants in 3.2% (11/347). In all, five infrequent BRAF alterations were detected: (i) c.1795_1797dupACA (p.T599dup); (ii) c.1801A>G (p.K601E); (iii) c.1799_1801delTGA (p.V600_K601>E); (iv) c.1799_1814>A (p.V600_S605>D); and (v) c.1798_1810delinsA (p.V600_W604>R). The last BRAF variant has never been described in the literature. Western blot analysis and immunofluorescence both revealed a variegated reactivity pattern, again emphasizing the peculiar role of every specific BRAF genetic alteration. In silico analysis of the samples studied revealed a stabilization of the "active" geometrical conformation of the B-raf enzyme associated with the activated and productive state of the kinase domain. CONCLUSIONS: Rare BRAF variants were found in 1.6% of all thyroid malignancies, all clustered around the codon V600, in the binding pocket named A-loop, confirming its crucial role in the enzymatic activation of the B-Raf protein. These mutations were associated mainly with the activation of key effectors in the mitogen-activated protein kinase pathway, but a simultaneous stimulation of the PI3k/Akt cascade was demonstrated in some cases. The rare BRAF variants were not generally associated with an aggressive behavior of the PTC. To our knowledge, this is the largest series of thyroid cancers analyzed to identify and functionally characterize rare BRAF variants.

Circulating cell-free DNA, SLC5A8 and SLC26A4 hypermethylation, BRAF(V600E): A non-invasive tool panel for early detection of thyroid cancer.

PURPOSE: In the latest years, high levels of circulating cell-free DNA (cf-DNA) have been found to be associated with cancer diagnosis and progression, and cf-DNA has become a potential candidate as biomarker for tumor detection. cf-DNA has been investigated in plasma or serum of many tumor patients affected by different malignancies, but not yet in thyroid cancer (TC). Furthermore, in TC cells the capability to metabolize iodine is frequently lost. SLC5A8 and SLC26A4 genes are both involved in the iodine metabolism, and SLC5A8 hypermethylation status is associated with the BRAF(V600E) mutation, which is the most frequent genetic event underlying the development of papillary TC. The aim of our study is the development of a new non-invasive tool for the diagnosis and prognosis of TC based on cf-DNA, SLC5A8 and SLC26A4 hypermethylation, and BRAF(V600E) analysis. METHODS: cf-DNA was measured by quantitative real-time PCR in nine cases of anaplastic thyroid cancer (ATC), 58 medullary thyroid cancers (MTC), five of synchronous medullary and follicular thyroid cancers (SMFC), 23 follicular adenomas (FA), 86 papillary thyroid cancers (PTC). A control group of 19 healthy subjects was taken. Moreover, in the PTC group we analyze the state of hypermethylation of SLC5A8 and SLC26A4, BRAF(V600E) mutation, and their involvement in the loss of function of the thyroid. RESULTS: cf-DNA showed a high ability to discriminate healthy individuals from cancer patients. cf-DNAALU83 and cf-DNAALU244 values were significantly correlated with the histological type of TC (P-value < 0.0001). A significant increase in the amount of cf-DNAALU83 and cf-DNAALU244 when methylation occurs was observed (P-value = 0.02). A correlation between BRAF(V600E) and cf-DNAALU244/ALU83 was also found (P-value = 0.02). CONCLUSIONS: According to our experimental results, the panel including cf-DNA, SLC5A8 and SLC26A4 hypermethylation, and BRAF(V600E) analysis appears easy, reproducible, and non-invasive for the diagnosis on TC. Its possible implication in clinical setting remains to be elucidated.

Characterization of a novel complex BRAF mutation in a follicular variant papillary thyroid carcinoma.

INTRODUCTION: Activating mutations of the BRAF oncogene are frequently detected in papillary thyroid carcinoma (PTC) and have been associated with a worse prognosis. The amino acid substitution V600E accounts for 90% of all oncogenic BRAF mutations and is typically detected in classic PTCs, whereas other less frequent BRAF mutations seem to be associated with other PTC histotypes. CASE: Screening for activating BRAF mutations in a series of 83 PTCs identified the most common V600E mutation in 39 cases (histologically, 38 classic PTCs and 1 sclerosing variant PTC) and a complex in-frame mutation involving amino acids V600-S605 in a stage III multicentric follicular variant PTC, occurring in a 50-year-old female patient, who was affected by hypothyroidism in autoimmune thyroiditis and had a family history of PTC and autoimmune thyroiditis. Since the identified BRAF mutation was novel in the literature, bioinformatic modeling was performed to predict its impact on BRAF activity. Although the mutation resulted in loss of a phosphorylation site in the activation loop of BRAF, it was predicted to increase BRAF kinase activity by mimicking an activating phosphorylation. CONCLUSIONS: This study, which reports a new BRAF mutation, highlights the usefulness of bioinformatic modeling in the prediction of functional effects of new mutations and indicates that mutation-specific screening tests might miss some rare BRAF mutations. These facts should be taken into consideration in the molecular diagnosis of thyroid cancer and in the design of therapeutic protocols based on inhibitors of the BRAF pathway.