Increasing diagnosis of thyroid papillary carcinoma follicular variant in south-east Anatolian region: comparison of characteristics of classical papillary and follicular variant thyroid cancers

The inhibition of Beclin1-dependent autophagy sensitizes PTC cells to ABT737-induced death

ABT737 is used as a specific BCL2 inhibitor, which can treat papillary thyroid carcinoma (PTC). However, the effect of ABT737 on PTC cell apoptosis is limited. Moreover, BCL2 inhibition causes the activation of Beclin1-dependent autophagy. Our study aimed to explore the effects of autophagy and Beclin1 on ABT737 efficacy in PTC. The experimental data showed that ABT737 synchronously enhanced autophagic activity and apoptosis level in PTC cells. ABT737 also promoted the dissociation of BCL2-Beclin1 and BCL2-Bax complexes. Autophagy inhibitors, Bafilomycin A1 and 3-MA, enhanced the inhibitory effect of ABT737 on the survival and function in PTC cells. Consistently, autophagy inhibition with Beclin1 pharmacological inhibitor (spautin-1) also enhanced the efficacy of ABT737. Additionally, ABT737 at low-dose promoted LC3 conversion in PTC cells, and did not affect PTC cell apoptosis and survival. However, The efficacy of low-dose of ABT737 in PTC cell apoptosis and survival was displayed with the addition of Bafilomycin A1, 3-MA or spautin-1. In conclusion, the limited role of ABT737 in PTC cell apoptosis is attributed to its promoting effect on Beclin1-dependent autophagy. Therefore, autophagy inhibition based on Beclin1 downregulation can enhance the sensitivity of PTC cells to ABT737-induced death.

TAT-Beclin 1 represses the carcinogenesis of DUSP4-positive PTC by enhancing autophagy

BACKGROUND

DUSP4 is a pro-tumorigenic molecule of papillary thyroid carcinoma (PTC). DUSP4 also exists as an autophagic regulator. Moreover, DUSP4, as a negative regulator of MAPK, can prevent Beclin 1 from participating in autophagic response. This study aimed to explore whether TAT-Beclin 1, a recombinant protein of Beclin 1, could inhibit the tumorigenesis of DUSP4-positive PTC by regulating autophagy.

METHODS

First, we divided PTC tissues into three groups according to DUSP4 expression levels by immunohistochemical analyses, and evaluated the relationship between autophagic molecules (Beclin 1 and LC3II) and DUSP4 using Western blotting assays. After overexpression of DUSP4 by lentiviral transduction, the in vitro and in vivo roles of TAT-Beclin 1 on DUSP4-overexpressed PTC cells were assessed (including autophagic activity, cell survival and function, and tumor growth). The roles of TAT-Beclin 1 in the survival of DUSP4-silenced PTC cells were also evaluated.

RESULTS

Our results showed that the expression levels of autophagic proteins decreased with the increase of DUSP4 expression in PTC tissues. In PTC cells, DUSP4 overexpression-inhibited autophagic activity (including Beclin 1 expression, LC3 conversion rate and LC3-puncta formation) and -promoted cell proliferation and migration were reversed by TAT-Beclin 1 administration. In vivo assays also showed that DUSP4-overexpressed PTC cells had stronger tumorigenic ability and weaker autophagic activity, which was blocked by TAT-Beclin 1 administration.

CONCLUSION

TAT-Beclin 1, as an autophagic promoter, could repress the carcinogenesis of DUSP4-positive PTC, which implies that the use of TAT-Beclin 1 for the PTC patients' treatment might be determined according to the DUSP4 level in their tumors.

DUSP4 inhibits autophagic cell death in PTC by inhibiting JNK-BCL2-Beclin1 signaling

Dual specificity phosphatase 4 (DUSP4) is a prognostic marker and potential target of papillary thyroid carcinoma (PTC); however, the molecular mechanism underlying DUSP4-regulated PTC carcinogenesis is unknown. DUSP4 is a negative regulator of the autophagy promoter, JNK. This study explored the relationship between DUSP4 and JNK-mediated autophagic cell death in PTC, and the roles of DUSP4 in PTC using gain-of-function and loss-of-function assays. In addition, we further identified the significance of the JNK-BCL2-Beclin1-autophagy signaling pathway on DUSP4-regulated PTC carcinogenesis by combining knockdown of DUSP4 with a JNK-specific inhibitor (SP600125). We found that knockdown of DUSP4 promoted the phosphorylation of JNK and BCL2 in PTC cells, and enhanced the release of Beclin1 from the BCL2-Beclin1 complex. Knockdown of DUSP4 promoted autophagy and the death of PTC cells. The death and autophagy enhanced by knockdown of DUSP4 was reversed by the JNK inhibitor. We further extended the in-vitro experiments by subcutaneously injecting nude mice with K1 cells transfected with DUSP4-silencing vector. In-vivo assays showed that knockdown of DUSP4 not only inhibited tumor growth, but also promoted the phosphorylation of JNK and BCL2 and the expression of LC3II. In conclusion, DUSP4 inhibits BCL2-Beclin1-autophagy signaling by negatively regulating JNK activity, thus inhibiting PTC oncogenesis. The data from this study contribute to the prevention and cure of PTC.

A 15 year institutional experience of well-differentiated follicular cell-derived thyroid carcinomas; impact of the new 2017 TNM and WHO Classifications of Tumors of Endocrine Organs on the epidemiological trends and pathological characteristics

PURPOSE

Our study aimed to describe the evolution of the rate of pathological subtypes of well-differentiated follicular-cell derived thyroid carcinomas (DTCs) in the Department of Pathology, Emergency County Hospital Targu-Mures, Romania over a 15 year period and to assess the impact the new 2017 WHO and TNM classifications of thyroid tumors had on our cases.

METHODS

The pathological data were retrieved from the original pathological reports. After applying the exclusion criteria the remaining cases were reviewed on a double-headed microscope and reclassified according to the 2017 WHO and TNM staging system. The follow-up data were collected from the Institute of Oncology Cluj-Napoca, Romania.

RESULTS

Our study included 396 cases of DTCs (375 papillary, 11 follicular, and 10 Hürthle cell carcinomas). PTCs revealed a significant increasing trend over the study period, whereas follicular and Hurthle cell carcinomas remain rare; 125/131 of noninvasive encapsulated follicular variant PTC (EFVPTC) were reclassified as noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTPs), resulting in a 33.3% reduction in the number of PTCs. According to 2017 TNM stage-grouping 31% of 271 patients with DTC were downstaged. Follow-up data were available for most of the patients (65.7%, mean period 58.1 months). All patients with noninvasive EFVPTC were disease free at the last clinical assessment.

CONCLUSIONS

The increasing rate of PTC was maintained even after exclusion of NIFTP. By applying 2017 TNM criteria, a significant number of DTC cases were downstaged into a more favorable group. Follow-up data highlight the indolent behavior of noninvasive EFVPTCs reclassified as NIFTPs.

Completion Thyroidectomy in Patients Diagnosed with Papillary Thyroid Cancer: Is There a Predictive Factor for Contralateral Lobe Tumor?

Objectives:

Completion thyroidectomy (CT) is defined as the removal of the residual thyroid tissue in the case of detected malignancy after lobectomy for an indeterminate or non-diagnostic biopsy. Factors such as tumor diameter, aggressive histology, extrathyroidal spread, and positive surgical margin in papillary thyroid cancer (PTC) constitute CT indications. However, the type of surgery is controversial especially in patients with a tumor diameter of 1-4 cm. Determination of predictive factors for contralateral lobe tumors (CLTs) in PTC may be helpful for rough or excessive treatment of patients with this common thyroid pathology.

The aim of the present study was to determine the predictive factors and rate of detection of CLTs after CT in patients with papillary thyroid carcinoma after lobectomy.

Methods:

Medical records of patients who underwent lobectomy with the final histological diagnosis of papillary thyroid carcinoma for the study period 2011 to 2016 were reviewed. Demographic data of the patients, diameter, multicentricity and subtype of tumor, extrathyroidal spread, and vascular invasion rate were obtained. Patients were divided into 2 groups as final histological examination after CT revealed benign (Group 1) and malignant (Group 2).

Results:

Data of 49 patients were retrospectively analyzed during the study period. The female-to-male ratio was 33/16. The mean age of the patients was 47.59 (23–77) years. Groups 1 and 2 consisted of 30 and 19 patients, respectively. No significant difference was found between the two groups regarding demographic data and tumor characteristics.

Conclusion:

Despite the fact that we have not been detecting any predictive factor in predicting the presence of tumor on the contralateral lobe in our study, the detection of a tumor on the contralateral lobe is frequent.

Follicular morphological characteristics may be associated with invasion in follicular thyroid neoplasms with papillary-like nuclear features

The newly proposed nomenclature and diagnostic criteria for encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC), the noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), could improve the consistency and accuracy of diagnosing this entity. Diagnosis of NIFTP requires evaluation of the complete tumor border or capsule. The presence of tumor invasion in follicular thyroid neoplasms with papillary-like nuclear features has been recently discussed by many authors. In this study, we examined the predictive value and association of follicular morphological characteristics with the tumor invasion. In addition, we analyzed the association between tumor encapsulation and molecular profile in EFVPTC/NIFTP cases. A total of 106 cases of FVPTC were included in the study. The tumors were grouped based on the presence of tumor capsule and characteristics of tumor border, as 1) completely encapsulated tumors without invasion, 2) encapsulated tumors with invasion, 3) infiltrative tumors without a capsule. Clinicopathological features, histomorphological features [nuclear criteria, minor diagnostic features, follicles oriented perpendicular to tumor border/capsule (FOPBC)] and molecular alterations in BRAF, NRAS, and KRAS genes were evaluated. FOPBC were significantly more frequently seen in encapsulated tumors with invasion (p = 0.008). The nuclear features were not associated with the presence of encapsulation and characteristics of tumor border. BRAF mutation was more frequent in infiltrative tumors, while NRAS mutation was more frequent in encapsulated tumors, but the results were not statistically significant (p = 0.917). In conclusion, FOPBC histomorphological feature may be associated with tumor invasion in EFVPTC/NIFTP. Additionally, BRAF/KRAS/NRAS mutation analysis may prevent inadequate treatment in these patients.

Invasive follicular variant of papillary thyroid cancer harboring the NRAS mutation Q61K and presenting with bone metastasis-A case report

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A patient with invasive follicular variant of papillary thyroid cancer presented with bone metastasis.

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The thyroid tumor harbored an isolated RAS mutation.

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The report challenges recent views that thyroid tumors with isolated RAS mutations may have a non-aggressive clinical course and may be candidates for conservative management.

Introduction

The follicular variant of papillary thyroid cancer (FVPTC) can be noninvasive or invasive. The invasive form of FVPTC commonly harbors BRAF mutations whereas RAS mutations are more often associated with noninvasive FVPTC and a favorable clinical outcome.

Case report

A 47-year-old man presented with a metastasis to his right iliac bone as the initial manifestation of a 1.6 cm invasive FVPTC. After total thyroidectomy, the patient underwent additional treatment, including thyroid hormone suppressive treatment to non-detectable TSH levels, repeated courses of radioiodine treatment, external beam radiation, and treatment with the tyrosine kinase inhibitor sorafenib. Despite these therapeutic efforts, the disease progressed with growth of the iliac mass and additional metastatic spread to cervical and lumbar vertebrae causing increasing pain and disability. The patient succumbed to the disease four years after presentation. Retrospective next-generation sequencing of the primary tumor using a pan-cancer targeted mutation and gene fusion panel revealed NRAS Q61K mutation and no other oncogenic alterations.

Discussion

The study challenges the concept that thyroid neoplasms with isolated RAS mutations are often associated with favorable clinical behavior and may be candidates for conservative management.

Conclusion

An isolated RAS mutation in invasive FVPTC may be associated with an aggressive clinical behavior.

High expression of metadherin correlates with malignant pathological features and poor prognostic significance in papillary thyroid carcinoma

BACKGROUND

Metadherin (MTDH) protein, also called astrocyte elevated gene-1 (AEG-1) is over expressed in a variety of malignant tumours, and is closely related to tumour invasion and the poor prognosis.

OBJECTIVE

This study tries to explore the clinical pathological significance of MTDH expression in a large cohort of patients with PTC.

DESIGN AND PATIENTS

Immunohistochemistry was used to detect MTDH expression in 156 cases of PTC, 6 cases of anaplastic thyroid carcinoma (ATC), 10 cases of multinodular goitre (MNG) and 10 cases of thyroid adenoma tissues who received a thyroid operation between June 2003 and July 2008.

MEASUREMENTS

Clinical pathological data of 156 cases of PTC were analysed according to MTDH expression. The Kaplan-Meier method was used to plot survival curves and log-rank test to compare the postoperative survival results. The prognostic meaning of MTDH expression in PTC was evaluated by Cox regression analysis.

RESULTS

The positive expression rates of MTDH in PTC and ATC tissues were 37·2% (58/156) and 50% (3/6), respectively, and MTDH positive expression rates were both 10% (1/10) in MNG and thyroid adenoma tissues. High MTDH expression in PTC was associated with larger tumour size (P = 0·030), high rates of lymph node (P = 0·041) and distant metastasis (P = 0·028), but no relation with the patient age, gender, tumour multicenter, extrathyroid invasion and tumour grade. High MTDH expression was associated with recurrence-free survival (RFS) and disease-specific survival rate (DSS) (P = 0·014, P = 0·001, respectively). Cox regression analysis showed that high MTDH expression was independent prognostic indicators for RFS and DSS in patients with PTC (P = 0·023 and P = 0·035, respectively).

CONCLUSION

High MTDH expression in PTC might play an important role in tumour growth and metastasis, and targeting MTDH treatment might have potential therapeutic value for patients with PTC.

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.

Genetic alterations in thyroid tumors from patients irradiated in childhood for tinea capitis treatment

OBJECTIVE

Exposure to ionizing radiation at young age is the strongest risk factor for the occurrence of papillary thyroid carcinoma (PTC). RET/PTC rearrangements are the most frequent genetic alterations associated with radiation-induced PTC, whereas BRAF and RAS mutations and PAX8-PPARG rearrangement have been associated with sporadic PTC. We decided to search for such genetic alterations in PTCs of patients subjected in childhood to scalp irradiation.

DESIGN

We studied 67 thyroid tumors from 49 individuals irradiated in childhood for tinea capitis scalp epilation: 36 malignant (12 cases of conventional PTC (cPTC), two cPTC metastases, 20 cases of follicular variant PTC (FVPTC), one oncocytic variant of PTC and one follicular carcinoma) and 31 follicular thyroid adenomas.

METHODS

The lesions were screened for the BRAF(V600E) and NRAS mutations and for RET/PTC and PAX8-PPARG rearrangements.

RESULTS

BRAF(V600E) mutation was detected in seven of 14 (50%) cPTC and two of 20 FVPTC (10%) (P=0.019). NRAS mutation was present in one case of FVPTC (5%). RET/PTC1 rearrangement was found, by RT-PCR, in one of 17 cases (5.9%) and by fluorescence in situ hybridization in two of six cases (33%). PAX8-PPARG rearrangement was not detected in any carcinoma. None of the follicular adenomas presented any of the aforementioned genetic alterations.

CONCLUSIONS

The prevalence of BRAF(V600E) mutation in our series is the highest reported in series of PTCs arising in radiation-exposed individuals. The prevalence of RET/PTC1 rearrangement fits with the values recently described in a similar setting.

MCM3 protein expression in follicular and classical variants of papillary thyroid carcinoma

Minichromosome maintenance (MCM) proteins are needed as licensors in the DNA replication of eukaryotic cells and transcriptional control of MCM genes has critical role in the regulation of MCM functions. Different MCM protein family members are proposed as diagnostic or prognostic markers in various cancers due to their increased proliferative potential. Among MCM family members, minichromosome maintenance protein 3 (MCM3) expressions in both mRNA and protein levels were shown to be associated with papillary thyroid carcinoma (PTC). But, the usability of MCM3 in some histological variants of PTC might be controversial due to tissue specific molecular heterogeneities. In follicular variant of papillary thyroid carcinoma (FVPTC), a number of genes including MCM3 were shown to be differentially expressed which were specific to this kind of variant. Using immunohistochemistry method, MCM3 protein expression levels were compared in FVPTC, classic variant of papillary thyroid carcinoma (CVPTC), and multi-nodular goiter (MNG) tissues in a group of 32 cases. There was meaningful differences between MNG vs. FVPTC (p = 0.016) and MNG vs. CVPTC (p = 0.019) while there was no significant difference in the comparison FVPTC vs. CVPTC (p = 0.15). Four of the 5 CVPTC cases having surrounding tissue invasion had high expression values. For FVPTC and CVPTC, MCM3 protein expression results were parallel to our previous mRNA expression study while there was downregulation in protein expression despite the increased expression of MCM3 mRNA in MNG suggesting tissue-specific post-transcriptional events in benign thyroid neoplasms of which should be focused on. Moreover, the relatively lower MCM3 protein expression in FVPTC comparing to CVPTC could be due to a different tumorigenic pathway favored in this type of tissue.