Development Of Papillary Thyroid Cancer Research Articles

A case-control study of urinary levels of iodine, perchlorate and thiocyanate and risk of papillary thyroid cancer

BackgroundThe incidence of thyroid cancer has recently increased worldwide. With the exception of radiation exposure, the effects of potential risk factors on thyroid cancer incidence remain controversial. ObjectivesThe association between exposure to iodine, perchlorate, and thiocyanate and papillary thyroid cancer (PTC) incidence was evaluated and risk factors were predicted. MethodsA pair-matching case-control study was performed including 116 age- and sex-matched PTC cases and 116 non-PTC controls. Iodine, perchlorate, and thiocyanate concentrations in urine specimens were determined by inductively coupled plasma mass spectrometry and ultra-performance liquid chromatography–tandem mass spectrometry. The association between iodine, perchlorate, and thiocyanate urinary concentrations and PTC was evaluated using univariable conditional regression logistic analysis followed by multivariable conditional logistic regression analyses with backward stepwise selection to predict risk factors for PTC. ResultsAfter adjusting for confounders and creatinine standardization, urinary concentrations of iodine [odds ratio (OR) = 11.01, 95% confidence interval (CI): 1.97–30.52] and perchlorate (OR = 2.27, 95% CI: 1.03–5.03) were associated with the risk of PTC, whereas urinary thiocyanate concentration showed a negative association (OR = 0.24, 95% CI: 0.09–0.65). ConclusionsIncreased exposure to iodine and perchlorate may affect PTC development, whereas high thiocyanate exposure may have a beneficial effect.

Molecular genetic factors in the development of papillary thyroid cancer in the Kazakh population

Introduction. In the last decade several population studies on the association of the genes NKX2-1 and FOXE1 with sporadic papillary thyroid cancer were conducted. In the Kazakh population of similar work to date were not conducted. The aim of this study was to study the genetic association of the FOXE1 (rs9655313) and NKX2-1 (rs944289) oncomarkers with papillary thyroid cancer in the Kazakh population.
 Materials and methods. We conducted a case-control study that allows us to retrospectively evaluate the association of NKX2-1 and FOXE1 genes and papillary thyroid cancer.
 Results. The frequency distribution of FOXE1 rs965513 polymorphism in the group of papillary thyroid cancer and the control group detected by healthy individuals was significantly different (χ2 = 100.09, D.f. = 2, p = 0.000). In the group of cases, the AA genotype (17.5%) was in three times more often compared with the control group (5.1%). The GG variant had a lower frequency in the group of persons of papillary thyroid cancer (37.9%) against the control group (61.4%), the odds ratio (OR) in the FOXE1 rs965513 group was 2.367. The distribution of the NKX2-1 (rs944289) polymorphism frequencies in the compared groups of values were significantly different (χ2 = 100.09, D.f. = 2, p = 0.000). In the group of cases, the genotype of TT (30.5%) against the control group (20.7%) was 1.5 times more common. The SS variant had a lower frequency of occurrence in the group of persons of papillary thyroid cancer (19.8%) against the control group (28.9%), OR in NKX2-1 (rs944289) group was 1.46.
 Conclusion. Carrying out screening for carriers of FOXE1 rs965513 and NKX2-1 (rs944289) can become an effective means of early diagnosis with a high frequency of its spread and associations with cases of papillary thyroid cancer in the Kazakh population.

Differential expression profile of CXCR3 splicing variants is associated with thyroid neoplasia. Potential role in papillary thyroid carcinoma oncogenesis?

Papillary thyroid cancer (PTC) is the most prevalent endocrine neoplasia. The increased incidence of PTC in patients with thyroiditis and the frequent immune infiltrate found in PTC suggest that inflammation might be a risk factor for PTC development. The CXCR3-ligand system is involved in thyroid inflammation and CXCR3 has been found upregulated in many tumors, suggesting its pro-tumorigenic role under the inflammatory microenvironment. CXCR3 ligands (CXCL4, CXCL9, CXCL10 and CXCL11) trigger antagonistic responses partly due to the presence of two splice variants, CXCR3A and CXCR3B. Whereas CXCR3A promotes cell proliferation, CXCR3B induces apoptosis. However, the relation between CXCR3 variant expression with chronic inflammation and PTC development remains unknown. Here, we characterized the expression pattern of CXCR3 variants and their ligands in benign tumors and PTC. We found that CXCR3A and CXCL10 mRNA levels were increased in non-metastatic PTC when compared to non-neoplastic tissue. This increment was also observed in a PTC epithelial cell line (TPC-1). Although elevated protein levels of both isoforms were detected in benign and malignant tumors, the CXCR3A expression remained greater than CXCR3B and promoted proliferation in Nthy-ori-3-1 cells. In non-metastatic PTC, inflammation was conditioning for the CXCR3 ligands increased availability. Consistently, CXCL10 was strongly induced by interferon gamma in normal and tumor thyrocytes.Our results suggest that persistent inflammation upregulates CXCL10 expression favoring tumor development via enhanced CXCR3A-CXCL10 signaling. These findings may help to further understand the contribution of inflammation as a risk factor in PTC development and set the basis for potential therapeutic studies.

DNA Mismatch Repair Deficiency Promotes Genomic Instability in a Subset of Papillary Thyroid Cancers.

Efficient DNA damage repair by MutL-homolog DNA mismatch repair (MMR) enzymes, MLH1, MLH3, PMS1 and PMS2, are required to maintain thyrocyte genomic integrity. We hypothesized that persistent oxidative stress and consequent transcriptional dysregulation observed in thyroid follicles will lead to MMR deficiency and potentiate papillary thyroid tumorigenesis. MMR gene expression was analyzed by targeted microarray in 18 papillary thyroid cancer (PTC), 9 paracarcinoma normal thyroid (PCNT) and 10 normal thyroid (NT) samples. The findings were validated by qRT-PCR, and in follicular thyroid cancers (FTC) and follicular thyroid adenomas (FTA) for comparison. FOXO transcription factor expression was also analyzed. Protein expression was assessed by immunohistochemistry. Genomic integrity was evaluated by whole-exome sequencing-derived read-depth analysis and Mann-Whitney U test. Clinical correlations were assessed using Fisher's exact and t tests. Microarray and qRT-PCR revealed reduced expression of all four MMR genes in PTC compared with PCNT and of PMS2 compared with NT. FTC and FTA showed upregulation in MLH1, MLH3 and PMS2. PMS2 protein expression correlated with the mRNA expression pattern. FOXO1 showed lower expression in PMS2-deficient PTCs (log2-fold change -1.72 vs. -0.55, U=11, p<0.05 two-tailed). Rate of LOH, a measure of genomic instability, was higher in PMS2-deficient PTCs (median 3 and 1, respectively; U=26, p<0.05 two-tailed). No correlation was noted between MMR deficiency and clinical characteristics. MMR deficiency, potentially promoted by FOXO1 suppression, may explain the etiology for PTC development in some patients. FTC and FTA retain MMR activity and are likely caused by a different tumorigenic pathway.

Retraction: Androgen receptor CAG and GGN repeat length variation contributes more to the tumorigenesis of osteosarcoma.

// Yongxiang Shi 1 , Weishan Chen 1 , Qinghuai Li 2 , Zhaoming Ye 1 1 Department of Orthopaedic Surgery, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China 2 Department of Medicine, 3rd Hospital of Henan Province, Henan, China Correspondence to: Zhaoming Ye, email: ye_zhaoming@163.com Keywords: osteosarcoma, papillary thyroid cancer, AR, repeat, CAG Received: May 24, 2016 Accepted: August 13, 2016 Published: September 08, 2016 ABSTRACT The androgen receptor ( AR ) is involved in the differentiation and growth of many cancers. We hypothesized that two microsatellite polymorphic variants, AR (CAG)n and (GGN)n repeats, were also associated with the development of Papillary thyroid cancer (PTC) and Osteosarcoma. In current study, we conducted two case-control studies in a Chinese population to investigate the possible relationship between these two AR repeat polymorphisms and the risk of PTC and Osteosarcoma. The AR CAG repeat length was significantly associated with both risk of PTC and Osteosarcoma. Subjects with shorter AR CAG repeats had a higher risk of developing PTC (OR = 1.47, 95% CI: 1.17–1.85, P = 0.001) and Osteosarcoma (OR = 1.53, 95% CI: 1.19–1.97, P = 9.2 x 10 –4 ). Specifically, shorter GGN repeats also contribute a significant increased risk of Osteosarcoma (OR = 1.35, 95% CI: 1.03–1.77, P = 0.030). Our results contribute to a better understanding of the complex hormone related mechanisms underlying PTC and Osteosarcoma.

E2F8, a direct target of miR-144, promotes papillary thyroid cancer progression via regulating cell cycle

BackgroundThyroid cancer is the most common malignancy of endocrine system, and papillary thyroid cancer (PTC) is the most common subtype. E2F8, a novel identified E2F family member, was reported to associate with progression of several human cancers, however, its clinical significance and biological role in PTC remain unknown.MethodsE2F8 or miR-144 expression profiles in PTC tissues were obtained from The Cancer Genome Atlas (TCGA) datasets, and the correlation of E2F8 expression with clinicopathological features was analyzed in a cohort PTC patients. The effects of E2F8 and miR-144 on proliferation were evaluated both in vitro and in vivo. Luciferase reporter assay was used to determine E2F8 was a direct target of miR-144.ResultsE2F8 was widely upregulated in PTC tissues, and overexpression of E2F8 was correlated with more aggressive clinicopathological features. In contrast, we found that silence of E2F8 significantly suppressed proliferation of PTC cells by inducing G1-phase arrest via downregulating Cyclin D1 (CCND1) both in vitro and in vivo. We also identified miR-144 as a tumor-suppressive microRNA that directly targeted E2F8 to inhibit proliferation of PTC cells in vitro and in vivo. Moreover, miR-144 was widely downregulated in PTC, where its expression correlated inversely with E2F8 expression.ConclusionsOur results demonstrate a new miR-144/E2F8/CCND1 regulatory axis controlling PTC development, which may offer a potential prognostic and therapeutic strategy.Trial registrationNo applicable.

Iodine intake as a risk factor for BRAF mutations in papillary thyroid cancer patients from an iodine-replete area.

Both deficient and excessive iodine intake leads to thyroid disease, which shows U-shaped curves. Our previous study showed that a relatively low [urinary iodine concentration (UIC) <300μg/L] and extremely excessive (UIC ≥ 2500μg/L) iodine intake were associated with thyroid cancer in Korea, an iodine-replete area. Papillary thyroid cancer (PTC) accounts for more than 97 % of thyroid cancer and 80% or more PTC cases harbor the BRAF mutation in Korea. We aimed to investigate the relationship between iodine intake and the prevalence of the BRAF mutation in PTC in Korea. UIC was measured by inductively coupled plasma mass spectrometry. The BRAF mutation was detected using both allele-specific polymerase chain reaction and mutant enrichment with 3'-modified oligonucleotide sequencing. Risk factors for the occurrence of BRAF mutations in PTC were evaluated using multivariate logistic regression models. The median UIC in all patients with PTC was 287μg/L (range from 7 to 7, 426μg/L). Nearly half of the patients (102/215, 47%) belonged to the excessive iodine intake category (UIC ≥ 300μg/L) according to the WHO iodine recommendations. The frequency of BRAF mutations was lowest in the 300-499μg/L UIC group; it was significantly different compared to the relatively low (UIC < 300μg/L) and more than excessive (UIC ≥ 500μg/L) iodine intake groups. UIC was an independent predictor for BRAF mutations in PTC. The multivariate-adjusted odds ratios (95% confidence intervals) in the relatively low and more than excessive iodine intake groups for the BRAF mutation were 4.761 (1.764-12.850) and 6.240 (2.080-18.726), respectively, compared to the 300-499μg/L UIC group. Relatively low iodine intake and more than excessive iodine intake seem to be significant risk factors for the occurrence of BRAF mutations in the thyroid and, therefore, may be risk factors for the development of PTC in an iodine-replete area.

Upregulation of the ESR1 Gene and ESR Ratio (ESR1/ESR2) is Associated with a Worse Prognosis in Papillary Thyroid Carcinoma: The Impact of the Estrogen Receptor α/β Expression on Clinical Outcomes in Papillary Thyroid Carcinoma Patients.

A gender disparity exists with respect to the incidence of papillary thyroid cancer (PTC), suggesting that sex hormones such as estrogen play a role in PTC development and progression. In this study, we compared estrogen receptor gene expression patterns in PTCs to determine the clinical significance of estrogen gene expression in PTC. We analyzed ESR1 and ESR2 messenger RNA expression counts using data from The Cancer Genome Atlas (TCGA). To validate the results of TCGA analysis, we analyzed microarray data (GSE 54958) from the Gene Expression Omnibus. ESR1 gene expression and ESR ratio (ESR1/ESR2) were significantly higher in PTC tissues than in paired normal thyroid tissues (mean 659.427 vs. 264.045 for ESR1, 92.017 vs. 19.064 for ESR ratio). Among female patients, ESR1 expression and ESR ratio were negatively correlated with increased age. ESR1 expression and ESR ratio were higher in patients with classic PTC, lymphovascular invasion, BRAF V600E mutation, and radioiodine therapy. Classification analysis demonstrated that higher ESR1 expression and a higher ESR ratio faced a worse overall survival (hazard ratio 6.348 for ESR1, 4.031 for ESR ratio). Validation microarray analysis demonstrated that ESR1 expression and ESR ratio were higher in tumor tissues, classic PTC, and BRAF V600E. Higher ESR1 expression and a higher ESR ratio were associated with aggressive prognostic factors and worse overall survival in female PTC patients. Our results suggest that ESR1 and ESR ratio can be used as prognostic markers to predict female patient survival and have potential as a therapeutic target.

Elevated Concentrations of SERPINE2/Protease Nexin-1 and Secretory Leukocyte Protease Inhibitor in the Serum of Patients with Papillary Thyroid Cancer

Introduction. SERPINE2 and secretory leukocyte protease inhibitor (SLPI) are proteins with anticoagulant properties which could promote solid tumor growth. However, their role in the pathogenesis of thyroid cancer has not been determined. Materials and Methods. The aim of this study was to assess serum SERPINE2 and SLPI concentrations in a group of 36 patients with papillary thyroid cancer (PTC) and a group of 19 subjects with multinodular nontoxic goiter (MNG). The control group (CG) consisted of 20 healthy volunteers. Blood samples were collected one day before surgery. Serum SERPINE2 and SLPI concentrations were measured using specific ELISA methods. Results. Significantly higher concentrations of SERPINE2 and SLPI were found in patients with PTC as compared with MNG and controls. Positive correlation was found between SERPINE2 and SLPI concentrations in PTC patients. The levels of SERPINE2 and SLPI did not differ significantly between MNG and healthy controls. Conclusions. Our results indicate that SERPINE2 and SLPI play a significant role in the development of papillary thyroid cancer and imply that the evaluation of serum concentrations of both anticoagulant molecules may be considered as additional marker for the differentiation of malignancies during the preoperative diagnosis of patients with thyroid gland tumors.

Androgen receptor CAG and GGN repeat length variation contributes more to the tumorigenesis of osteosarcoma.

The androgen receptor (AR) is involved in the differentiation and growth of many cancers. We hypothesized that two microsatellite polymorphic variants, AR (CAG)n and (GGN)n repeats, were also associated with the development of Papillary thyroid cancer (PTC) and Osteosarcoma. In current study, we conducted two case-control studies in a Chinese population to investigate the possible relationship between these two AR repeat polymorphisms and the risk of PTC and Osteosarcoma. The AR CAG repeat length was significantly associated with both risk of PTC and Osteosarcoma. Subjects with shorter AR CAG repeats had a higher risk of developing PTC (OR = 1.47, 95% CI: 1.17–1.85, P = 0.001) and Osteosarcoma (OR = 1.53, 95% CI: 1.19–1.97, P = 9.2 × 10–4). Specifically, shorter GGN repeats also contribute a significant increased risk of Osteosarcoma (OR = 1.35, 95% CI: 1.03–1.77, P = 0.030). Our results contribute to a better understanding of the complex hormone related mechanisms underlying PTC and Osteosarcoma.

Intracellular signalling mechanisms in thyroid cancer

Abstract Background Thyroid cancer is the most common malignancy of the endocrine system, the papillary variant accounts for 80–90% of all diagnosed cases. In the development of papillary thyroid cancer, BRAF and RAS genes are mainly affected, resulting in a modification of the system of intracellular signalling proteins known as “protein kinase mitogen-activated” (MAPK) which consist of “modules” of internal signalling proteins (Receptor/Ras/Raf/MEK/ERK) from the cell membrane to the nucleus. In thyroid cancer, these signanling proteins regulate diverse cellular processes such as differentiation, growth, development and apoptosis. MAPK play an important role in the pathogenesis of thyroid cancer as they are used as molecular biomarkers for diagnostic, prognostic and as possible therapeutic molecular targets. Mutations in BRAF gene have been correlated with poor response to treatment with traditional chemotherapy and as an indicator of poor prognosis. Objective To review the molecular mechanisms involved in intracellular signalling of BRAF and RAS genes in thyroid cancer. Conclusions Molecular therapy research is in progress for this type of cancer as new molecules have been developed in order to inhibit any of the components of the signalling pathway (RET/PTC)/Ras/Raf/MEK/ERK; with special emphasis on the (RET/PTC)/Ras/Raf section, which is a major effector of ERK pathway.

Mecanismos de señalización intracelular en cáncer de tiroides

BackgroundThyroid cancer is the most common malignancy of the endocrine system, the papillary variant accounts for 80-90% of all diagnosed cases. In the development of papillary thyroid cancer, BRAF and RAS genes are mainly affected, resulting in a modification of the system of intracellular signaling proteins known as «protein kinase mitogen-activated» (MAPK) which consist of «modules» of internal signaling proteins (Receptor/Ras/Raf/MEK/ERK) from the cell membrane to the nucleus. In thyroid cancer, these signanling proteins regulate diverse cellular processes such as differentiation, growth, development and apoptosis. MAPK play an important role in the pathogenesis of thyroid cancer as they are used as molecular biomarkers for diagnostic, prognostic and as possible therapeutic molecular targets. Mutations in BRAF gene have been correlated with poor response to treatment with traditional chemotherapy and as an indicator of poor prognosis. ObjectiveTo review the molecular mechanisms involved in intracellular signaling of BRAF and RAS genes in thyroid cancer. ConclusionsMolecular therapy research is in progress for this type of cancer as new molecules have been developed in order to inhibit any of the components of the signaling pathway (RET/PTC)/Ras/Raf/MEK/ERK; with special emphasis on the (RET/PTC)/Ras/Raf section, which is a major effector of ERK pathway.

Abstract 2775: Characterization of transcriptional and epigenetic signatures of benign thyroid adenomas: Can we improve preoperative diagnosis of thyroid nodules

Abstract Introduction: It has been estimated that as many as 50,000 patients in the United States receive unnecessary thyroidectomies due to the inability to distinguish benign thyroid nodules from malignant ones. Up to 30% of fine needle aspirates performed for thyroid nodules diagnosis are indeterminate due to overlapping cytological features between benign and malignant nodules. At present, commercially-available diagnostic tests for thyroid nodules are based on the molecular differences observed between thyroid cancer compared to normal thyroid tissue. However, the molecular signature of benign thyroid nodules is neither well-characterized nor included in currently available diagnostic panels. The objective of this study was to determine whether thyroid adenomas (TA) are distinct from normal thyroid tissue and papillary thyroid cancer (PTC). Methods: Whole transcriptome analysis was used to assess differences in transcriptional activity in 9 TA and 12 PTC tissue pairs (with matched normal adjacent thyroid tissue from the same patients). In order to evaluate epigenetic alterations associated with TA development, we used reduced representation bisulfite sequencing (RRBS) in 114 thyroid specimens (40 PTC, 28 TA and 46 matching adjacent thyroid tissues). This approach provides single base resolution of DNA methylation genome wide. Results: According to our data, transcriptome activity divided analyzed specimens into three separate groups: PTC, TA and adjacent thyroid tissues. TA demonstrated a unique transcriptional pattern, distinct from both normal adjacent thyroid tissue and PTC. Similar results were obtained by analysis of epigenetic alterations in these tissues. According to the clustering analysis of DNA methylation patterns, the majority (18 of 28) of benign nodules forms a separate cluster, distinct from adjacent normal thyroid and PTC tissue clusters. Within this group, 14 of 28 TA demonstrated a distinct DNA methylation signature associated with TA-specific hypermethylation. In fact, only 4 of 28 TA demonstrated a DNA methylation signature similar to normal thyroid tissue, suggesting that the majority of TA is not equivalent to normal thyroid. Conclusion: According to whole transcriptome analysis and genome wide analysis of DNA methylation, TA is frequently associated with specific transcriptional and DNA methylation signatures compared to normal thyroid tissue and PTC. These data indicate that the majority of thyroid adenomas are associated with a unique molecular pathway that is distinct from PTC development. Use of the adenoma-specific molecular signature can be an essential factor in the improvement of PTC diagnostic panels, helping to reduce unnecessary thyroidectomies. Citation Format: Audrey H. Choi, Ryan Lew, Michael O’Leary, Yuman Fong, John H. Yim, Maria A. Hahn. Characterization of transcriptional and epigenetic signatures of benign thyroid adenomas: Can we improve preoperative diagnosis of thyroid nodules. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2775.

Plasma exosomal miR-21 and miR-181a differentiates follicular from papillary thyroid cancer.

Thyroid cancer (TC) is the most common endocrine malignancy and its incidence has increased over the last few decades. As has been revealed by a number of studies, TC tissue's micro-RNA (miRNA) profile may reflect histological features and the clinical behavior of tumor. However, alteration of the miRNA profile of plasma exosomes associated with TC development has to date not been explored. We isolated exosomes from plasma and assayed their characteristics using laser diffraction particle size analysis, atomic force microscopy, and western blotting. Next, we profiled cancer-associated miRNAs in plasma exosomes obtained from papillary TC patients, before and after surgical removal of the tumor. The diagnostic value of selected miRNAs was evaluated in a large cohort of patients displaying different statuses of thyroid nodule disease. MiRNA assessment was performed by RT-qPCR. In total, 60 patients with different types of thyroid nodal pathology were included in the study. Our results revealed that the development of papillary TC is associated with specific changes in exosomal miRNA profiles; this phenomenon can be used for differential diagnostics. MiRNA-31 was found to be over-represented in the plasma exosomes of patients with papillary TC vs. benign tumors, while miRNA-21 helped to distinguish between benign tumors and follicular TC. MiRNA-21 and MiRNA-181a-5p were found to be expressed reciprocally in the exosomes of patients with papillary and follicular TC, and their comparative assessment may help to distinguish between these types of TC with 100% sensitivity and 77% specificity.

Epigenetic Alterations and Canonical Pathway Disruption in Papillary Thyroid Cancer: A Genome-wide Methylation Analysis.

Alterations in DNA methylation have been demonstrated in a variety of malignancies, including papillary thyroid cancer (PTC). The full extent of dysregulation in PTC and the downstream affected pathways remains unclear. Here we report a genome-wide analysis of PTC methylation, the dysregulation of various canonical pathways, and assess its potential as a diagnostic test. A discovery set utilized 49 PTCs and matched normal controls from The Cancer Genome Atlas. Another set of 16 PTCs and 13 normal controls were used as a replication set. Genome-wide methylation analysis was done using Illumina 450K methylation chips. Differentially methylated loci (DML) were identified by comparing PTC and matched normal tissues. DML were defined as false-discovery rate p<0.05 and absolute Δβ≥0.2. DML were then analyzed for pathway and disease commonalities using Qiagen Ingenuity Pathway Analysis. Of 485,577 CpG sites analyzed, 1226 DML were identified in our discovery and replication sets, and 1061 (86.5%) DML showed hypomethylation when comparing tumor with normal tissue. Support vector machine classification was able to differentiate benign from malignant tissue in 107 (94.7%) of 113 tested samples, including 15 (83.3%) of 18 samples lacking a clearly deleterious mutation. Statistically significant associations with multiple canonical pathways, diseases, and biofunctions were observed including PI3K, PTEN, wnt/β-catenin, and p53. Epigenetic dysregulation of multiple canonical pathways are associated with the development of PTC. This methylation signature shows promise as a future adjunctive screening test for thyroid nodules.

KRASG12D-mediated oncogenic transformation of thyroid follicular cells requires long-term TSH stimulation and is regulated by SPRY1

KRASG12D can cause lung cancer rapidly, but is not sufficient to induce thyroid cancer. It is not clear whether long-term serum thyroid stimulating hormone (TSH) stimulation can promote KRASG12D-mediated thyroid follicular cell transformation. In the present study, we investigated the effect of long-term TSH stimulation in KRASG12D knock-in mice and the role of Sprouty1 (SPRY1) in KRASG12D-mediated signaling. We used TPO-KRASG12D mice for thyroid-specific expression of KRASG12D under the endogenous KRAS promoter. Twenty TPO-KRASG12D mice were given anti-thyroid drug propylthiouracil (PTU, 0.1% w/v) in drinking water to induce serum TSH and 20 mice were without PTU treatment. Equal number of wild-type littermates (TPO-KRASWT) was given the same treatment. The expression of SPRY1, a negative regulator of receptor tyrosine kinase (RTK) signaling, was analyzed in both KRASG12D-and BRAFV600E-induced thyroid cancers. Without PTU treatment, only mild thyroid enlargement and hyperplasia were observed in TPO-KRASG12D mice. With PTU treatment, significant thyroid enlargement and hyperplasia occurred in both TPO-KRASG12D and TPO-KRASWT littermates. Thyroids from TPO-KRASG12D mice were six times larger than TPO-KRASWT littermates. Distinct thyroid histology was found between TPO-KRASG12D and TPO-KRASWT mice: thyroid from TPO-KRASG12D mice showed hyperplasia with well-maintained follicular architecture whereas in TPO-KRASWT mice this structure was replaced by papillary hyperplasia. Among 10 TPO-KRASG12D mice monitored for 14 months, two developed follicular thyroid cancer (FTC), one with pulmonary metastasis. Differential SPRY1 expression was demonstrated: increased in FTC and reduced in papillary thyroid cancer (PTC). The increased SPRY1 expression in FTC promoted TSH-RAS signaling through PI3K/AKT pathway whereas downregulation of SPRY1 by BRAFV600E in PTC resulted in both MAPK and PI3K/AKT activation. We conclude that chronic TSH stimulation can enhance KRASG12D-mediated oncogenesis, leading to FTC. SPRY1 may function as a molecular switch to control MAPK signaling and its downregulation by BRAFV600E favors PTC development.

Association between single nucleotide polymorphisms of upstream transcription factor 1 (USF1) and susceptibility to papillary thyroid cancer.

Thyroid cancer, predominantly by papillary thyroid cancer (PTC), is a malignant tumour of endocrine system with increasing incidence rate worldwide. Upstream transcription factor 1 (USF1) regulates a variety of biological processes by transactivation of functional genes. In this study, we investigated the association between USF1 polymorphisms and PTC risk. A total of 334 patients with PTC, 186 patients with benign nodules (BN) and 668 healthy controls were enrolled in our study. Tag-SNPs were identified in Chinese Han in Beijing (CHB) from International HapMap Project Databases. Genomic DNAs were extracted by TaqMan Blood DNA kits. SNPs of USF1 were genotyped by TaqMan SNPs genotyping assay. Odds ratios (OR) and corresponding 95% confidence interval (CI) were used to assess the association between USF1 genetic variants and PTC risk. The statistical analyses were carried out with spss 13.0 software. Five tag-SNPs were retrieved to capture all the genetic variants of USF1. Among the five tag-SNPs, genetic variants in rs2516838, rs3737787 and rs2516839 have significant association with PTC risk. The rs2516838 polymorphisms dominant model (CG+GG vs CC: OR = 0·71; 95% CI: 0·52-0·97; P = 0·033) and allelic model (C vs G: OR = 0·031; 95% CI: 0·56-0·97; P = 0·031) indicated it may act as a protective factor against PTC. On the contrary, the results of rs3737787 polymorphisms: dominant model (CT+TT vs CC: OR = 1·55; 95%CI: 1·09-2·02; P = 0·001) and allelic model (C vs T: OR = 1·35; 95%CI: 1·10-1·64; P = 0·003), as well as the results of rs2516839 polymorphisms: dominant model (GA+AA vs GG: OR = 1·77; 95%CI: 1·31-2·38; P < 0·001) and allelic model (G vs A: OR = 1·36; 95%CI: 1·13-1·63; P = 0·014), revealed that they may act as risk factors for PTC. In this study, we found the SNPs of rs2516838 (mutant G alleles vs wild C alleles), rs3737787 (mutant T alleles vs wild C alleles) and rs2516839 (mutant A alleles vs wild G alleles) were significantly associated with PTC risk. Further large-scale studies with different ethnicities are still needed to validate our findings and explore the underlying mechanism of USF1 in PTC development.

Abstract 5280: A polymorphism of VEGFA is associated with susceptibility to extrathyroidal invasion of papillary thyroid cancer

Abstract Background: Vascular endothelial growth factor A (VEGFA) has pivotal roles in angiogenesis, vascular permeability, vasculogenesis, cellular growth, and cell migration. We investigated whether single nucleotide polymorphisms (SNPs) of the VEGFA gene are associated with the development of papillary thyroid cancer (PTC). We also assessed the relationships between VEGFA SNPs and the clinicopathologic characteristics such as the size of cancers (&amp;lt; 1 cm and ≥ 1 cm), numbers of cancers (unifocality and multifocality), location of cancers (one lobe and both lobe), extrathyroidal invasion (present and absent), and cervical lymph node metastasis (present and absent). Methods: One promoter SNP (rs699947, -2578A/C) and one 5′-untranslation region (5′UTR) SNP (rs2010963, +405C/G) in VEGFA were genotyped using direct sequencing in 94 PTC patients and 213 healthy controls. SNPStats, SNPAnalyzer, Helixtree, and Haploview version 4.2 were used to analyze genetic data. Multiple logistic regression models (codominant, dominant, recessive, and log-additive) were performed to evaluate odds ratios (ORs), 95% confidence intervals (CIs), and p values. Results: Two SNPs of VEGFA were not associated with the development of PTC. Also, haplotypes were not associated with PTC??. However, we found a relationship between the 5′UTR SNP rs2010963 and PTC with the extrathyroidal invasion (p = 0.0060 in codominant model, p = 0.0258 in dominant model, p = 0.0057 in recessive model, and p = 0.0060 in log-additive model). Allele frequencies of rs2010963 were different between the extrathyroidal invasion (-) and extrathyroidal invasion (+) groups (p = 0.0050). In Bonferroni correction, these correlations were also significant except the recessive model. Conclusion: Our results suggest that the 5′UTR SNP rs2010963 (+405C/G) of VEGFA may be associated with susceptibility to extrathyroidal invasion of PTC in Korean population. Note: This abstract was not presented at the meeting. Citation Format: Young Gyu Eun, Young Chan Lee, Jung-Woo Lee. A polymorphism of VEGFA is associated with susceptibility to extrathyroidal invasion of papillary thyroid cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5280. doi:10.1158/1538-7445.AM2015-5280

Promoter methylation of p16 and RASSF1A genes may contribute to the risk of papillary thyroid cancer: A meta-analysis.

The aim of the present meta-analysis was to investigate the correlation of promoter methylation of the p16 and Ras association domain family 1 isoform A (RASSF1A) genes with the risk of the development of papillary thyroid cancer (PTC). A number of electronic databases were searched without language restrictions as follows: Medline (1966-2013), the Cochrane Library database (Issue 12, 2013), Embase (1980-2013), CINAHL (1982-2013), Web of Science (1945-2013) and the Chinese Biomedical Database (CBM; 1982-2013). A meta-analysis was performed with the use of Stata statistical software. The odds ratios (ORs), ratio differences (RDs) and 95% confidence intervals (95% CIs) were calculated. In the present meta-analysis, eleven clinical cohort studies with a total of 734 patients with PTC were included. The results of the current meta-analysis indicated that the frequency of promoter methylation of p16 in cancer tissues was significantly higher compared with that in normal, adjacent and benign tissues (cancer tissues vs. normal tissues: OR=7.14; 95% CI, 3.30-15.47; P<0.001; cancer tissues vs. adjacent tissues: OR=11.90; 95% CI, 5.55-25.52; P<0.001; cancer tissues vs. benign tissues: OR=2.25; 95% CI, 1.67-3.03; P<0.001, respectively). The results also suggest that RASSF1A promoter methylation may be implicated in the pathogenesis of PTC (cancer tissues vs. normal tissues: RD=0.53; 95% CI, 0.42-0.64; P<0.001; cancer tissues vs. adjacent tissues: RD=0.39; 95% CI, 0.31-0.48; P<0.001; cancer tissues vs. benign tissues: RD=0.39; 95% CI, 0.31-0.47; P<0.001; respectively). Thus, the present meta-analysis indicates that aberrant promoter methylation of p16 and RASSF1A genes may play a crucial role in the pathogenesis of PTC.

High prevalence of papillary thyroid cancer in Korean women with insulin resistance.

The purpose of this study was to determine if hyperinsulinemia and/or insulin resistance are/is associated with the prevalence of papillary thyroid cancer (PTC) in Korean women. This study included 735 female patients with PTC and 537 female non-PTC control subjects. Multiple logistic regression analysis was performed to evaluate the associations between hyperinsulinemia/insulin resistance and the occurrence of PTC. The prevalence of PTC was significantly correlated with increased insulin, glucose levels, and a high homeostasis model of assessment-insulin resistance (HOMA-IR). The multivariate adjusted odds ratios for the prevalence of PTC in the highest quartile groups for insulin, glucose, and HOMA-IR were 2.88, 9.32, and 4.07 (all p < .001), respectively, compared with the lowest quartile groups. Pathological analyses revealed that increased serum glucose, insulin levels, and a higher HOMA-IR were associated with the multifocality of PTC. Hyperinsulinemia and/or insulin resistance may be associated with the development of PTC, but not disease severity in Korean women.