Molecular genetics of thyroid cancer

Study of single nucleotide polymorphism of vascular endothelium factor in patients with differentiated thyroid cancer

BACKGROUND

Genetic alterations and high levels of the vascular endothelial growth factor (VEGF) are presumptive risk factors for differentiated thyroid cancer (DTC).

OBJECTIVE

This work aims to study the presence of - 634G/C polymorphism of vascular endothelial growth factor (rs2010963) and its' serum level in patients with DTC and comparing these results with those of the control subjects.

MATERIAL AND METHOD

The study was a retrograde case-control study that included seventy patients with DTCin addition to seventy apparently healthy control subjects. Blood sample was taken and subjected to study of - 634G/C VEGF polymorphism (rs2010963) by real time PCR and measurement of its' plasma level by immunoassay kit (ELISA).

RESULTS

Regarding genotyping of VEGFA - 634G/C (rs2010963) polymorphism, there was significant increase in CG and GG genotypes (28.6%, 18.6% respectively) among patients compared to control subjects (20.0%, 4.3% respectively) and significant increase in CC genotype in control subjects (75.7%) compared to patients (52.9%), P = 0.001. The VEGF mean ± SD level was significantly elevated in patients compared to control subjects (1215.81 ± 225.78 versus 307.16 ± 91.81, P = 0.006). Moreover, there was significant increase in VEGF levels in patients with CG and GG genotypes (1295.9 ± 68.74, 1533.08 ± 109.95, respectively) compared to patients with CC genotype (1061 163.25), P = 0.001).

CONCLUSION

There was significant increase in GG and CG genotypes in patients with DTC compared to control subjects which may suggest a predisposing role for these genotypes in development of DTC. Moreover, there was significant increase in serum level of vascular endothelial growth factor in patients with GG and CG genotypes which may reflect the mechanism of these genotypes in development of DTC.

Diagnostic Reliability of the American College of Radiology Thyroid Imaging Reporting and Data System in Royal Commission Hospital, Kingdom of Saudi Arabia

BACKGROUND: The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) classified and predicted the risk of thyroid nodule malignancy with ultrasound scan scoring system. AIM: Hence, we aimed to investigate the value of the combined use of ultrasound ACR TI-RADS scoring and ultrasound-guided thyroid fine needle aspiration cytology (FNAC) based on the Bethesda System for Reporting Thyroid Cytology (TBSRTC) for assessing the accuracy tests of diagnosing low and high-risk thyroid nodules of ACR TI-RADS. METHODS: We enrolled 392 patients with thyroid nodules who underwent ultrasound scanning and scoring using the ACR TI-RADS classification along with ultrasound-guided thyroid FNAC and scoring with TBSRTC. The two methods were grouped as low and high risk of malignancy to evaluate the accuracy of ACR TI-RADS. RESULTS: Three hundred and ninety-two patients were enrolled in the study. The mean (Standard deviation [SD]) age was 46.03 (13.96) years, 332 (84.7%) were females and the mean (SD) of body mass index was 31.90 (22.32) kg/m2 and Vitamin D 17.65 (11.15) nmol/L. The mean (SD) for thyroid function test was 5.37 (44.16) mmol/L for thyroid-stimulating hormone, 1.48 (1.49) ng/dL for free thyroxine (FT4), and 2.69 (0.70) nmol/L for free triiodothyronine (FT3). Most of the participants were euthyroid (63.8%), but 28.6% had hypothyroidism and 7.7% had hyperthyroidism. The accuracy tests of ACR TI-RADS in relation to TBSRTC, were sensitivity (87.8%), specificity (65.2%), positive predictive value (29.8%), and negative predictive value (97%). The area under the curve = 0.590, 95% CI = 0.530–0.650, p ˂ 0.006. CONCLUSION: ACR TI-RADS is a simple, practical, and reliable scoring system for assessing thyroid nodule; it has a better overall diagnostic performance and the ability to exclude unnecessary FNAC with high negative predictive value.

FOXE1 Gene Dosage Affects Thyroid Cancer Histology and Differentiation In Vivo

The transcription factor Forkhead box E1 (FOXE1) is a key player in thyroid development and function and has been identified by genome-wide association studies as a susceptibility gene for papillary thyroid cancer. Several cancer-associated polymorphisms fall into gene regulatory regions and are likely to affect FOXE1 expression levels. However, the possibility that changes in FOXE1 expression modulate thyroid cancer development has not been investigated. Here, we describe the effects of FOXE1 gene dosage reduction on cancer phenotype in vivo. Mice heterozygous for FOXE1 null allele (FOXE1^+/−) were crossed with a BRAF^V600E-inducible cancer model to develop thyroid cancer in either a FOXE1^+/+ or FOXE1^+/− genetic background. In FOXE1^+/+ mice, cancer histological features are quite similar to that of human high-grade papillary thyroid carcinomas, while cancers developed with reduced FOXE1 gene dosage maintain morphological features resembling less malignant thyroid cancers, showing reduced proliferation index and increased apoptosis as well. Such cancers, however, appear severely undifferentiated, indicating that FOXE1 levels affect thyroid differentiation during neoplastic transformation. These results show that FOXE1 dosage exerts pleiotropic effects on thyroid cancer phenotype by affecting histology and regulating key markers of tumor differentiation and progression, thus suggesting the possibility that FOXE1 could behave as lineage-specific oncogene in follicular cell-derived thyroid cancer.

Influencers on Thyroid Cancer Onset: Molecular Genetic Basis

Thyroid cancer, a cancerous tumor or growth located within the thyroid gland, is the most common endocrine cancer. It is one of the few cancers whereby incidence rates have increased in recent years. It occurs in all age groups, from children through to seniors. Most studies are focused on dissecting its genetic basis, since our current knowledge of the genetic background of the different forms of thyroid cancer is far from complete, which poses a challenge for diagnosis and prognosis of the disease. In this review, we describe prevailing advances and update our understanding of the molecular genetics of thyroid cancer, focusing on the main genes related with the pathology, including the different noncoding RNAs associated with the disease.

Downregulation of CSN6 attenuates papillary thyroid carcinoma progression by reducing Wnt/β-catenin signaling and sensitizes cancer cells to FH535 therapy

The incidence of thyroid cancer has increased worldwide at a rate higher than that of any other cancer. CSN6 is overexpressed in many types of cancers, and such expression is linked to oncogenic activity. However, the detailed biological functions of CSN6 in papillary thyroid cancer (PTC) have not been well characterized. We investigated CSN6 expression in PTC specimens and cell lines. We used short-hairpin RNA-mediated gene silencing to explore the biological effects of CSN6 depletion in PTC cells. The combined effects of CSN6 silencing and FH535 therapy were assessed in terms of cell viability. The mechanism by which CSN6 regulated β-catenin expression was also analyzed. CSN6 levels were determined by real-time polymerase chain reaction (PCR) (mRNA), Western blotting, and immunochemistry (protein). The CCK-8 and migration assays and orthotopic xenograft transplantation were used to investigate the biological effects of CSN6. We assessed the combined effects of CSN6 silencing and FH535 on cell viability in vitro. We also analyzed the relationship between the CSN6 level and clinical pathological status. CSN6 was overexpressed in human PTCs, and loss of CSN6 attenuated tumor proliferation and migration both in vitro and in vivo. CSN6 stabilized β-catenin and facilitated the epidermal-to-mesenchymal transition (EMT) in PTC cells. CSN6 positively regulated β-catenin expression in a β-Trcp-dependent manner and triggered expression of several EMT-related genes regulated by β-catenin. CSN6 silencing sensitized PTC cells to FH535 therapy via downregulation of the Wnt/β-catenin signaling pathway. Finally, in PTC patients, the level of CSN6 was significantly (inversely) correlated with tumor size, the presence of multifocal lesions, and TNM stage. CSN6 overexpression in PTC is a strong indicator of enhanced tumor aggressiveness. CSN6 promotes PTC progression by inducing the EMT. CSN6 knockdown sensitizes PTC cells to FH535 therapy via downregulation of the Wnt/β-catenin signaling pathway.