Detecting TSHR mRNA from peripheral blood of patients with differentiated thyroid cancer rules out nonaggressive cases

BACKGROUND

Early diagnosis of thyroid cancer is hampered by the inability of fine-needle aspiration biopsy (FNAB) to accurately classify ∼30% of cases while preoperative cancer staging detects lymph nodal involvement in only half of cases. Liquid biopsy may present an accurate, non-invasive alternative for preoperative thyroid nodule assessment. Thyrotropin receptor (TSHR) mRNA, a surrogate marker for circulating cancer cells (CTC), may be an option for early detection of malignancy from peripheral blood, but requires methodological improvements. We aimed to investigate if TSHR mRNA can be detected in low sample volumes by employing an ultrasensitive method - droplet digital PCR (ddPCR).

METHODS

Less that 5 mL of blood was collected from 47 patients with thyroid nodules (25 benign, 22 malignant). RNA was isolated from the fraction of mononuclear cells where CTCs segregate. Samples were analyzed for the presence of TSHR mRNA by ddPCR.

RESULTS

TSHR mRNA was detectable in 4 mL sample volumes, with the test having good specificity (80%) but modest diagnostic accuracy (68.1%). Combining TSHR mRNA with ultrasound features and FNAB diagnosis, the test reaches high rule-out performances (sensitivity=90% and NPV=88.2%). Strikingly, TSHR mRNA correctly classified all samples with thyroid capsule invasion, lymph node metastasis and extrathyroidal extension. If aggressiveness is defined using these parameters, TSHR mRNA test reaches 100% sensitivity and 100% NPV for detecting high-risk cases.

CONCLUSIONS

Employing ddPCR for TSHR mRNA improves its measurement by enabling detection in sample volumes common for laboratory testing. The test displays high prognostic performance, showing potential in preoperative risk assessment.

Challenges and current advances in the methodology of thyroglobulin measurements

Thyroglobulin (Tg) is a large protein secreted exclusively by the thyroid gland. In a clinical setting, it is measured for the purpose of follow-up of thyroidectomy patients. However, Tg measurements are often impeded by the presence of Tg autoantibodies and/or heterophylic antibodies that interfere with most measuring platforms. This presents a global problem in thyroid cancer patients who need to be postoperatively monitored for recurrent or residual disease. Therefore, in this paper we offer an overview of the existing methodologies and alternative approaches for Tg measurements that are a focus of research worldwide. These include Tg mRNA measurements, exosomal Tg detection, the use of alternative analytes (liquid biopsies) and the development of new approaches for preanalytical sample treatment.

BRAFV600E, BANCR, miR-203a-3p and miR-204-3p in Risk Stratification of PTC Patients

In order to enhance the risk stratification of papillary thyroid carcinoma (PTC) patients, we assessed the presence of the most common mutation in PTC (BRAFV600E) with the expression profiles of long non-coding RNA activated by BRAFV600E (BANCR) and microRNAs, which share complementarity with BANCR (miR-203a-3p and miR-204-3p), and thereafter correlated it with several clinicopathological features of PTC. BRAFV600E was detected by mutant allele-specific PCR amplification. BANCR and miRs levels were determined by quantitative RT-PCR. Bioinformatic analysis was applied to determine the miRs' targets. The expression profile of miR-203a-3p/204-3p in PTC was not affected by BRAFV600E. In the BRAFV600E-positive PTC, high expression of miR-203a-3p correlated with extrathyroidal invasion (Ei), but the patients with both high miR-203a-3p and upregulated BANCR were not at risk of Ei. In the BRAFV600E-negative PTC, low expression of miR-204-3p correlated with Ei, intraglandular dissemination and pT status (p < 0.05), and the mutual presence of low miR-204-3p and upregulated BANCR increased the occurrence of Ei. Bioinformatic analysis predicted complementary binding between miR-203a-3p/204-3p and BANCR. The co-occurrence of tested factors might influence the spreading of PTC. These findings partially describe the complicated network of interactions that may occur during the development of PTC aggressiveness, potentially providing a new approach for high-risk PTC patient selection.

Expression of pY397-FAK and Its miR Regulators Drive Dedifferentiation in the Thyroid Neoplasia Spectrum

Thyroid carcinomas are growing malignancies worldwide. They encompass several diagnostic categories with varying degrees of dedifferentiation. Focal adhesion kinase is involved in cellular communication and locomotion. It is regulated on a posttranscriptional level by miR-7, miR-135a, and miR-138 and on a posttranslational level by autophosphorylation at Y397 (pY397-FAK). We related regulators of FAK with histologic dedifferentiation, clinicopathological factors, and differential diagnosis in the thyroid neoplasia spectrum. We classified 82 cases into 5 groups with increasing aggressiveness: healthy tissue, follicular and classical variants of papillary thyroid carcinoma (PTC), dedifferentiated PTC, and anaplastic carcinoma. MiRs were analyzed by RT-qPCR. Protein expression of pY397-FAK was analyzed by immunohistochemistry (separately in the membrane, cytoplasm, and nuclear compartment) and Western blot. All three miRs were upregulated in healthy tissue compared to malignant, while pY397-FAK was downregulated. MiRs and pY397-FAK were not mutually correlated. MiR-135a-5p was decreasing while membranous and cytoplasmic pY397-FAK increased with dedifferentiation. Neither miR correlated with clinicopathological factors. MiR-135a-5p, miR-138-5p, and membranous and cytoplasmic pY397-FAK discriminated the follicular from the classical variant of PTC. Disturbances of FAK regulation on different levels contribute to neoplastic dedifferentiation. pY397-FAK exerts its oncogenic role in the membrane and cytoplasm. Diagnostically, miRs-135a-5p, miR-138-5p, and membranous and cytoplasmic pY397-FAK differentiated between classical and follicular PTC.

MiR-203a-3p, miR-204-3p, miR-222-3p as useful diagnostic and prognostic tool for thyroid neoplasia spectrum

PURPOSE

The challenge in the diagnosis and treatment of thyroid carcinoma is to correctly classify neoplasias with overlapping features and to identify the high-risk patients among those with a less aggressive form, in order to personalize the treatment of thyroid carcinoma patients accordingly.

METHODS

MiR-203a-3p, miR-204-3p, and miR-222-3p levels were determined in 99 cases of thyroid neoplasias (77 papillary thyroid carcinomas (PTC) of diverse variants, 12 follicular thyroid adenomas (FTA) and 10 nodular goiters (NG)) along with 99 adjacent non-malignant thyroid tissues using quantitative RT-PCR. The results were evaluated in comparison with the clinicopathological features of the patients and available TCGA data.

RESULTS

Down-regulated miR-203a-3p indicates the presence of thyroid tumor (PTC or FTA) with high sensitivity (75%) and specificity (73%), while its up-regulation indicates NG. If miR-203a-3p is down-regulated, up-regulated miR-204-3p with high sensitivity (83.3%) and specificity (74.4%) indicates FTA presence, while up-regulated miR-222-3p, with high sensitivity (76.6%) and specificity (75.0%), points to PTC. The expression of miR-204-3p and miR-222-3p depends on the PTC subtype (P < 0.05). While the deregulated expression of tested miRs is associated with a long-range of unfavorable clinicopathological parameters of PTC, only abundant expression of miR-222-3p may be used as an independent predictive factor for the presence of extrathyroid invasion and advanced pTNM stage of PTC (P < 0.05).

CONCLUSION

Successive evaluation of miR-203a-3p, miR-204-3p, and miR-222-3p expression can help in the differential diagnosis of thyroid neoplasias. A high relative value of miR-222-3p expression is an independent predictive factor for the presence of extrathyroid invasion and advanced pTNM stage of PTC. The panel consisting of miR-203a-3p, miR-204-3p, and miR-222-3p could be used as a diagnostic and prognostic tool for personalizing the treatment of thyroid cancer patients.

Elevated BANCR expression levels have different effects on papillary thyroid carcinoma progression depending on the presence of the BRAFV600E mutation

INTRODUCTION

The role of BRAF-activated non-protein coding RNA (BANCR) in papillary thyroid carcinoma (PTC) is controversial, its clinical significance is unclear and no study has correlated the presence of the BRAFV600E mutation in PTC with BANCR expression.

METHODS

BANCR levels in PTC and matched nonmalignant thyroid epithelial tissues from 85 patients were determined using quantitative RT-PCR. BRAFV600E was detected by mutant allele-specific PCR amplification. The results were correlated with clinicopathological characteristics of the patients.

RESULTS

The presence of BRAFV600E associates with lower relative BANCR expression (RBE) in PTC (p = 0.008). RBE is down-regulated in BRAFV600E positive PTC, while it is unchanged or up-regulated in BRAFV600E negative PTC compared to the levels in paired nonmalignant tissue (p = 0.001). At the cut-off of 31.3%, sensitivity of fold change of BANCR for the presence of BRAFV600E is 68.0% and specificity is 67.2%. In BRAFV600E positive PTC up-regulated BANCR predicts lymph node metastasis (p = 0.001), while in BRAFV600E negative PTCs high RBE predicts thyroid capsule invasion (p = 0.028).

CONCLUSIONS

Depending on the presence of BRAFV600E, elevated BANCR levels demonstrated different effects on lymphatic spreading and local PTC invasion. Therefore, BANCR could be a useful prognostic biomarker in risk stratification of PTC patients.

Overexpression of epidermal growth factor receptor and its downstream effector, focal adhesion kinase, correlates with papillary thyroid carcinoma progression

Epidermal growth factor receptor (EGFR) and its downstream effector, focal adhesion kinase (FAK), have been shown to be overexpressed frequently in human malignancies and implicated in tumour aggressiveness. We aimed to investigate the relationship between EGFR and FAK expression and their possible correlation with the clinical phenotype of patients with papillary thyroid carcinoma (PTC). Expression profiles of EGFR and FAK were analysed in PTC tissue samples (n = 104) by immunohistochemistry and Western blotting. Additionally, EGFR and FAK were immunohistochemically analysed in 20 primary tumours paired with their metastatic tissue in lymph nodes. High expression of EGFR and FAK was found in 55.77% and 57.69% cases, respectively, with a strong positive association between them (P < 0.0001, Spearman's correlation coefficient = 0.844). Expression of each molecule and their coexpression correlated significantly with the presence of lymph node metastasis (LNM), degree of tumour infiltration, extrathyroid invasion and pT status of the patients. Western blot analysis confirmed that coexpression of high levels of EGFR and FAK correlated with adverse clinicopathological features. When compared to the corresponding primary tumour, increased or maintained high levels of EGFR and FAK were found in LNM, indicating their concordant expression during lymphatic spread. In conclusion, high levels of EGFR and its downstream effector, FAK, in association with lymphatic spread and tumour infiltration indicate their involvement in PTC progression and suggest that both molecules may predict its aggressive behaviour. Furthermore, FAK could be a potential target for anticancer therapy in patients with advanced thyroid cancer.

Coexpressed High Levels of VEGF-C and Active MMP-9 Are Associated With Lymphatic Spreading and Local Invasiveness of Papillary Thyroid Carcinoma

OBJECTIVES

Papillary thyroid carcinoma (PTC) usually has a good prognosis, but some patients develop an aggressive course of the disease, leading to a poor outcome. Vascular endothelial growth factor C (VEGF-C) and matrix metalloproteinase 9 (MMP-9) have been shown to play roles in tumor progression in various human malignancies.

METHODS

We analyzed VEGF-C and active MMP-9 expression profiles in PTC samples using immunohistochemistry and Western blotting.

RESULTS

Immunohistochemistry showed positive staining for VEGF-C and active MMP-9 in 83% and 57% of PTCs, respectively (n = 60), with a positive correlation between their expression levels (Spearman, P < .001). Concomitant high expression of VEGF-C and active MMP-9 correlated with the presence of lymph node metastasis (P  = .005), pT status (P  = .004), pTNM tumor stage (P  = .005), and particularly the degree of tumor infiltration (P < .001, Fisher exact test). Densitometric analysis of Western blot bands confirmed correlation between VEGF-C and active MMP-9 expression (Wilcoxon and Spearman tests) and significant association with the clinicopathologic parameters (Mann-Whitney and Kruskal-Wallis tests).

CONCLUSIONS

Association of coexpressed high levels of VEGF-C and active MMP-9 with lymphatic spreading and local invasiveness of PTC suggests their potential usefulness as predictive biomarkers of aggressive PTC behavior.