Papillary Thyroid Carcinoma Tumor Tissues Research Articles

The Act of Diminishing the RTRAF Expression in Benign Thyroid Tissues Represents a Potential Method for Impeding the Progression of Malignancy in Cells

Background: Thyroid cancer is the most common endocrine cancer, and women are almost three times more likely to develop it than men. Objectives: The etiology of thyroid cancer at the genetic level remains elusive. However, a potential involvement of the RNA Transcription, Translation, and Transport Factor (RTRAF) gene in the pathogenesis of this malignancy has been postulated. This gene has been shown to govern the expression of proteins that exert regulatory effects on the transition from the G1 to S phase of the cell cycle. Methods: For this study, 22 papillary thyroid carcinoma (PTC) tissues and 22 healthy tissues were collected. Additionally, 10 benign goiter tissues and 10 healthy tissues were gathered. RNA molecules were fixed, and complementary DNA (cDNA) was produced. Specific primers were used to measure the RTRAF gene expression. Statistical analysis was conducted using REST 2009 software. Results: Upon assessing the quality and quantity of RNA, it was ascertained that the extracted RNA molecules exhibited minimal damage and were found to be appropriately concentrated for cDNA production. The amplification of the RTRAF gene was carried out accurately, as evidenced by the melting curve. A noteworthy decline in the RTRAF gene expression was detected in the benign goiter tissue compared to the adjacent healthy tissue, with a relative expression of 0.154 and a statistical value of P = 0.002. Conversely, there was no significant difference in the RTRAF gene expression between PTC and the adjacent healthy tissue, with a P-value of 0.808. Conclusions: The reduced RTRAF gene expression in benign thyroid tumors may hinder cancer cell growth, as no difference was observed between malignant PTC tumor tissues and their healthy tissues.

The association of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α protein expression with clinicopathological characteristics in papillary thyroid carcinoma: A meta-analysis.

To investigate the correlation of hypoxia-inducible factor-1α (HIF-1α) and hypoxia-inducible factor-2α (HIF-2α) protein expression with clinicopathologic characteristics in patients with papillary thyroid carcinoma (PTC) through a meta-analysis. PubMed, Embase, Web of Science, Cochrane, CNKI, Wanfang, and VIP databases were searched from the establishment of the database to February 2023. The New castle-Ottawa Scale was used to evaluate the quality of the literature. Rev Man 5.3 and Stata14.0 were used to conduct a meta-analysis of the included studies. Twenty-eight articles with 2346 samples were included in the Meta-analysis. Compared with normal thyroid tissues, HIF-1α and HIF-2α proteins were highly expressed in PTC tumor tissues. High expression of HIF-1α protein was associated with tumor size (odds ratio [OR] = 4.50, 95% confidence interval [CI]: 2.88-7.04, P < .00001), lymph node metastasis (OR = 4.76, 95% CI: 3.78-5.99, P < .00001), TNM stage (OR = 3.67, 95% CI: 2.68-5.03, P < .00001), capsular invasion (OR = 2.30, 95% CI: 1.43-3.71, P = .0006 < .05), and extrathyroidal extension (OR = 10.96, 95% CI: 4.80-25.02, P < .00001). High expression of HIF-2α protein was associated with lymph node metastasis (OR = 4.18, 95% CI: 2.63-6.65, P < .00001), TNM stage (OR = 2.56, 95% CI: 1.36-4.82, P = .004 < .05), and capsular invasion (OR = 3.84, 95% CI: 1.66-8.88, P = .002 < .05). In addition, we concluded for the first time that there was a statistically significant difference in the expression of HIF-1α and HIF-2α in PTC patients (OR = 2.36, 95% CI: 1.26-4.42, P = .007 < .05). The high expression of HIF-1α and HIF-2α proteins is closely related to some clinicopathological parameters of PTC, and can provide potential biological indicators for the diagnosis and prognosis of PTC.

PD-L1 Expression and Ultrasound Characteristics in Papillary Thyroid Carcinoma and Its Effect on Recurrence.

Programmed death-ligand 1 (PD-L1) is a component of the tumor microenvironment, which is closely involved in the occurrence and development of tumors. We investigated the correlation between the expression of PD-L1 and ultrasound characteristics in papillary thyroid carcinoma (PTC) and its effect on recurrence. Fifty-two patients at the Department of General Surgery of Qingdao Municipal Hospital underwent thyroid ultrasonic examination before surgery and their clinicopathological variables were collected. Then, immunohistochemistry staining was conducted to evaluate the PD-L1 expression in tumors and adjacent normal tissues. The correlations of PD-L1 expression with clinicopathological and ultrasound characteristics were analyzed. The expression of PD-L1 was positive in 59.7% (40/67) of PTC tumor tissues. In clinicopathological analyses, PD-L1 positivity was related to multifocality of tumors (p=0.031). In analyses of ultrasound characteristics, the expression of PD-L1 was positively correlated with halo sign (p=0.035), capsular invasion (p=0.003), microcalcification (p=0.02), and recurrence (p=0.009). In multivariate logistic analysis of ultrasonic characteristics and recurrence of thyroid carcinoma, microcalcification [odds ratio=13.349, 95% confidence interval (CI)=2.052-86.832, p=0.007] and the halo sign (odds ratio=15.273, 95% CI=1.451-160.747, p=0.023) were factors associated with recurrence of PTC. In the multivariate Cox regression analysis, positive PD-L1 staining [hazard ratio (HR)=5.031, 95% CI=1.092-23.172, p=0.038] and a halo sign (HR=4.998, 95% CI=1.084-23.051, p=0.039) were independent predictors for poorer recurrence-free survival. Positive expression of PD-L1 predicted worse recurrence-free survival in the subgroup of patients with a halo sign (HR=6.537, 95% CI=1.863-22.94, p=0.037). Positive expression of PD-L1 in PTC affects the clinical and ultrasonic characteristics of the tumor and may negatively affect the prognosis of patients with PTC.

Bioinformatics analysis of downstream circRNAs and miRNAs regulated by Runt-related transcription factor 1 in papillary thyroid carcinoma.

This study sought to clarify the role of Runt-related transcription factor 1's (RUNX1's) regulation of downstream circular ribonucleic acid (circRNA) in the occurrence and development of papillary thyroid carcinoma (PTC) and to explore its mechanism of action. The levels of RUNX1 were analyzed in PTC tumor tissues and adjacent non-tumor tissues in different types and at different stages via reverse-transcription quantitative polymerase chain reaction (RT-qPCR). The expression pattern and functional role of RUNX1 were analyzed in PTC cells via RT-qPCR, Western blotting, and Transwell assays. This study explored the differential expression of circRNA and microRNA (miRNA) in cells after knocking down RUNX1 through high-throughput sequencing and examined the changes in downstream signaling pathways through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. RUNX1 was upregulated in PTC tissues, and the expression levels of RUNX1 were related to PTC stage. The knockdown of RUNX1 inhibited the proliferation, migration, and invasion of cells. The high-throughput sequencing results showed that after RUNX1 knockdown, 29 circRNAs (11 upregulated and 18 downregulated) and 20 miRNAs (8 upregulated and 12 downregulated) had the most significant differential expression. The GO analysis of the differential circRNA downstream genes showed that the iron channel-related pathways, endosomal transport, learning, and memory pathways had the largest number of differential genes, and the most significant changes. The KEGG analysis showed that there were 2 pathways with P values <0.05; that is, the glycosaminoglycan synthesis and transcription dysregulation pathways. The GO analysis of the differential miRNA downstream genes showed that the protein binding and cytoplasmic pathways had the largest number of differential genes and the greatest level of difference. The KEGG analysis showed that the tumor-related pathways, phosphatidylinositol-3-kinase and protein kinase B, glycoprotein, cytoskeleton, Ras, and Rap1 pathways changed the most significantly. RUNX1 is highly expressed in PTC. We conducted high-throughput sequencing to analyze the effect of knocking down RUNX1 on the levels of circRNA and miRNA in PTC. The GO and KEGG analyses revealed that the iron channel-related pathways, endosomal transport, learning and memory, glycosaminoglycan synthesis, and transcriptional disorder-related signaling pathways were enriched.

LncRNA DUXAP8 inhibits papillary thyroid carcinoma cell apoptosis via sponging the miR‑20b‑5p/SOS1 axis.

Papillary thyroid carcinoma (PTC) is the most common type of cancer in the endocrine system. Long non‑coding RNAs (lncRNAs) are associated with PTC progression. Therefore, the present study aimed to identify a novel lncRNA involved in PTC. Herein, dysregulated lncRNAs were analyzed in The Cancer Genome Atlas (TCGA)‑thyroid cancer (THCA) data. Furthermore, the association between double homeobox A pseudogene 8 (DUXAP8) gene expression and disease stage, and prognosis of patients with PTC was evaluated using the GEPIA online database, while the correlation between DUXAP8 expression and the clinicopathological characteristics of patients with PTC was analyzed by Chi‑square test. In addition, the biological effect of DUXAP8 expression on cell proliferation and apoptosis was also investigated. The protein and mRNA/microRNA (miRNA)/lncRNA expression levels were assessed by western blot analysis and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), respectively. The interaction between miR‑20b‑5p and DUXAP8 was verified using bioinformatics analysis, RNA RIP assay, dual luciferase reporter assay, western blot analysis and RT‑qPCR. The analysis of the TCGA‑THCA data revealed that DUXAP8 was one of the most significantly upregulated lncRNAs in PTC. This finding was further confirmed in tissues from patients with PTC. Increased DUXAP8 expression was associated with higher grade and poorer prognosis in patients with PTC. In PTC cell lines, silencing of DUXAP8 expression with small interfering RNA‑DUXAP8 (si‑DUXAP8) induced cell apoptosis and attenuated cell proliferation. Additionally, transfection of PTC cells with si‑DUXAP8 decreased the phosphorylation levels of MEK1/2 and ERK1/2, as well as downregulated the expression of son of sevenless1(SOS1), cyclinD1(CCND1) and c‑Myc. The results of the present study also revealed that miR‑20b‑5p could directly target DUXAP8. DUXAP8 expression was positively associated with that of SOS1, c‑Myc and CCND1 in the TCGA‑THCA data, and DUXAP8 level was positively correlated with that of SOS1 in PTC tumor tissues. Finally, transfection of PTC cells with the SOS1 overexpression plasmid, pcDNA3.1‑SOS1, rescued the effects of si‑DUXAP8 on cell proliferation and apoptosis. The present study was the first to identify DUXAP8 as a novel upregulated lncRNA in PTC, and provided new insights in understanding the effect of the lncRNA‑miRNA‑mRNA network in PTC.

SHCBP1 Promotes Papillary Thyroid Carcinoma Carcinogenesis and Progression Through Promoting Formation of Integrin and Collagen and Maintaining Cell Stemness.

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer with a rapidly increasing incidence globally. Bioinformatics analyses suggested that SHCBP1 (SHC SH2 Domain-Binding Protein 1) was significantly up-regulated in PTC tumor tissues, which was further confirmed by immunohistochemical staining and qPCR analyses in Xuzhou cohort. Moreover, the results indicated that the mRNA level of SHCBP1 was negatively associated with patients’ disease-free survival rate, and further analysis reveals that patients with high SHCBP1 expression tend to have more lymph node metastasis. Afterward, MTT, colony formation, cell-cycle assay, FACS apoptosis assay, invasion, migration, as well as scratch assay were performed to study the phenotypes change of PTC cells after knocking down SHCBP1. The in vivo subcutaneous tumor model was developed to study the proliferation ability of PTC cells after SHCBP1 knockdown. We show that knock down of SHCBP1 significantly inhibits PTC cell proliferation, cell cycle, invasion and migration in vivo and in vitro. Western blot and qRT-PCR showed that knockdown of SHCBP1 could significantly reduce MYC, KLF4, CD44, ITGA6, ITGB1, ITGB5, and COL4A2 expression at both RNA and protein levels, which indicated that SHCBP1 might be involved in PTC carcinogenesis and progression through targeting formation of integrin and collagen and cell stemness pathways, and can be a potential diagnosis biomarker and therapeutic target for PTC.

ANXA1 enhances tumor proliferation and migration by regulating epithelial-mesenchymal transition and IL-6/JAK2/STAT3 pathway in papillary thyroid carcinoma.

Background: Annexin A1 (ANXA1) was discovered to show various effects during tumor initiation and development in a tumor-specific manner. However, the function of ANXA1 in papillary thyroid carcinoma (PTC) has not been reported.Methods: Bioinformatic analyses, RT-PCR and immunohistochemistry were employed to determine the ANXA1 expression level in PTC. Both gain- and loss-of-function studies, including CCK-8, EdU assay, transwell experiment and wound-healing assay were used to investigate the role of ANXA1 in PTC progression. GSEA enrichment analysis was utilized to explore the potential mechanisms of ANXA1 mediated downstream signaling, and ELISA, RT-PCR and western blot were used to confirm the relevance.Results: ANXA1 expression was prominently upregulated in PTC tumor tissues. Ectopic expression of ANXA1 expedited PTC cell proliferation, migration and invasion, whereas ANXA1 knockdown exhibited the opposing trends. Mechanistic investigations showed that ANXA1 regulated epithelial-mesenchymal transition (EMT) and activated the IL-6/JAK2/STAT3 pathway to contribute to PTC malignant behaviors. In particular, loss of ANXA1 retarded tumor burden and suppressed lung metastasis in vivo.Conclusions: In conclusion, our findings identified ANXA1 as a pivotal oncogene during PTC carcinogenesis and ANXA1 might function as a promising therapeutic target and prognostic marker for PTC.

Circ_PSD3 promotes the progression of papillary thyroid carcinoma via the miR-637/HEMGN axis

AimsIn the present study, we aimed to uncover the potential functions of circular RNA (circRNA) pleckstrin and Sec7 domain containing 3 (circ_PSD3) in papillary thyroid carcinoma (PTC) development. Main methodsThe abundance of circ_PSD3, PSD3 messenger RNA (mRNA), microRNA-637 (miR-637) and hemogen (HEMGN; EDAG-1) mRNA was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was employed to measure cell cycle progression and cell apoptosis. Western blot assay was used to examine protein expression. The proliferation ability and motility of PTC cells were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assays, respectively. The interaction between miR-637 and circ_PSD3 or HEMGN was tested by dual-luciferase reporter assay. Animal experiments were used to explore the role of circ_PSD3 in PTC progression in vivo. Key findingsCirc_PSD3 was aberrantly up-regulated in PTC tumor tissues compared with adjacent normal tissues. Circ_PSD3 and HEMGN promoted the cell cycle progression, proliferation and metastasis and impeded the apoptosis of PTC cells. MiR-637 was a direct target of circ_PSD3, and miR-637 directly interacted with HEMGN mRNA in PTC cells. Circ_PSD3 silencing-induced effects in PTC cells were partly attenuated by the addition of anti-miR-637 or HEMGN overexpression plasmid. Circ_PSD3/miR-637/HEMGN regulated the activity of PI3K/Akt signal pathway in PTC cells. Circ_PSD3 silencing inhibited the tumor growth in vivo. SignificanceCirc_PSD3 promoted the progression of PTC through regulating miR-637/HEMGN axis and activating PI3K/Akt signaling. Circ_PSD3/miR-637/HEMGN signaling axis might be a potential target for PTC therapy.

Validation of MicroRNA-188-5p Inhibition Power on Tumor Cell Proliferation in Papillary Thyroid Carcinoma

Given the crucial role of microRNAs in the cellular proliferation of various types of cancers, we aimed to analyze the expression and function of a cellular proliferation-associated miR-188-5p in papillary thyroid carcinoma (PTC). Here we demonstrate that miR-188-5p is downregulated in PTC tumor tissues compared with the associated noncancerous tissues. We also validate that the miR-188-5p overexpression suppressed the PTC cancer cell proliferation. In addition, fibroblast growth factor 5 (FGF5) is observed to be downregulated in the PTC tumor tissues compared with the associated noncancerous tissues. Subsequently, FGF5 is identified as the direct functional target of miR-188-5p. Moreover, the silencing of FGF5 was found to inhibit PTC cell proliferation, which is the same pattern as miR-188-5p overexpression. These results suggest that miR-188-5p-associated silencing of FGF5 inhibits tumor cell proliferation in PTC. It also highlights the importance of further evaluating miR-188-5p as a potential biomarker and therapy target in PTC.

Overexpression of long noncoding RNA SLC26A4-AS1 inhibits the epithelial-mesenchymal transition via the MAPK pathway in papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC) is recognized as one of the most prevalent types of thyroid cancer with poor prognosis. Long noncoding RNA (lncRNA) has undergone an intensive study for their involvement in tumor treatment. This study intends to unravel the association of lncRNA SLC26A4-AS1 with PTC. Initially, PTC-related expression profiling data (GSE33630) was utilized to screen differentially expressed lncRNAs in PTC and the underlying mechanisms involved with the mitogen-activated protein kinase (MAPK) pathway. Moreover, PTC tumor tissues and paracancerous tissues were arranged to determine expressions of TP53, SLC26A4-AS1, and genes related to epithelial-mesenchymal transition (EMT) and the MAPK pathway. Furthermore, SLC26A4-AS1 was overexpressed or underexpressed and JNK was underexpressed through cell transfection to examine the effect of SLC26A4-AS1 on PTC via MAPK pathway. Besides, tumor formation in nude mice was used to verify the fore experiment. LncRNA SLC26A4-AS1 regulating TP53 had the potential to participate in PTC by regulating the MAPK pathway. SLC26A4-AS1 was expressed poorly in PTC. Notably, SLC26A4-AS1 elevated E-cadherin expression while it reduced that of ERK and Vimentin. In addition, the overexpression of SLC26A4-AS1 inactivated the MAPK pathway by promoting TP53 and decreased cell migration, proliferation, and invasion. In addition to all these effects, the overexpression of SLC26A4-AS1 promoted apoptosis of TPC-1 cells. Additionally, the overexpression of lncRNA SLC26A4-AS1 reduced xenograft tumor volume in nude mice. Furthermore, the effect of SLC26A4-AS1 overexpression was found to be promoted after the MAPK pathway inactivation. Taken together, the overexpression of lncRNA SLC26A4-AS1 coffered anti-oncogenic effects on PTC through the inactivation of the MAPK pathway.

MiR-96-5p promotes the proliferation, invasion and metastasis of papillary thyroid carcinoma through down-regulating CCDC67.

MicroRNAs (miRNAs) have been identified to play an important regulatory role in various biological behaviors of papillary thyroid carcinoma (PTC). However, the specific role and function of miR-96-5p in PTC remain unclear. Therefore, the aim of this study is to detect the expression of miR-96-5p in PTC, and to explore its exact function. The relative expression level of miR-96-5p in PTC tissues and cell lines was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). MiR-96-5p mimics or inhibitors were then constructed and transfected into cells to upregulate or downregulate miR-96-5p expression. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay and colony formation assay were employed to evaluate the proliferation of PTC cells. Meanwhile, transwell assay was employed to detect the invasion and metastasis of PTC cells. In addition, the underlying mechanism of miR-96-5p was identified by Luciferase reporter gene assay and Western blot analysis. The expression of miR-96-5p in PTC tissues and PTC-derived cell lines was significantly higher than that of normal controls. The overexpression of miR-96-5p remarkably promoted the proliferation, invasion and migration of PTC cells. However, knockdown of miR-96-5p significantly decreased cell growth and metastasis. CCDC67 was verified as a target gene of miR-96-5p in PTC. Further experiments demonstrated that the restoration of CCDC67 could significantly reduce the carcinogenic function of miR-96-5p. MiR-96-5p was remarkably upregulated in PTC tumor tissues and cells. In addition, it promoted cell growth, invasion, and migration via repressing CCDC67 expression.

Long noncoding RNA cancer susceptibility candidate 2 suppresses papillary thyroid carcinoma growth by inactivating the AKT/ERK1/2 signaling pathway.

Cancer susceptibility candidate 2 (CASC2) and long noncoding RNA (lncRNA) have been identified asa tumor suppressor in colorectal, lung, renal, and stomach cancer as well as in patient gliomas, but the function of CASC2 in papillary thyroid carcinoma (PTC) is not yet clear. The present study aimed to explore the effects of CASC2 in PTC. The CASC2 expression was measured in PTC samples and normal tissues by using quantitative real-time polymerase chain reaction. The lentiviral vectors were used to establish CASC2 overexpression models in PTC cell lines to determine the effects of CASC2 on cell proliferation, apoptosis, migration, and invasion. A tumor xenograft animal model was used to examine the functions of overexpression CASC2. CASC2 expression was significantly decreased in PTC tumor tissues than adjacent normal tissues. CASC2 downregulation in PTC tissues significantly correlated with the tumor size, the presence of multifocal lesions, and the advanced pathological stage. CASC2 overexpression suppressed the cell proliferation and promoted apoptosis in PTC cell lines and CASC2 overexpression resulted in the inactivation of protein kinase B (PKB/AKT) and extracellular signal-regulated kinases (ERK1/2). The regulatory effects of CASC2 on PTC cell biological behavior were further enhanced by mitogen-activated protein kinase kinase (MEK) inhibitor U0126 or AKT1/2/3 inhibitor MK-2206 2HCl. CASC2 overexpression suppressed tumor growth in PTC cells in xenograft mouse models. Our results indicated that CASC2 significantly suppressed tumorigenesis in PTC and CASC2 may serve as a novel prognostic marker or therapeutic target.

Yes-associated protein 1 promotes papillary thyroid cancer cell proliferation by activating the ERK/MAPK signaling pathway.

Yes-associated protein 1 (YAP1) stimulates cell proliferation, epithelial-to-mesenchymal transition, invasion and metastasis in several cancers. Here, we investigated the involvement of YAP1 in papillary thyroid carcinoma (PTC) by assessing YAP1 mRNA and protein levels in PTC tissues and matched normal thyroid epithelial tissues from 50 patients. YAP1 mRNA and protein levels were higher in PTC tumor tissues than in control tissues, and correlated positively with the levels of proliferation-related genes (KI67 and c-MYC). We also used lentiviral vectors to overexpress or silence YAP1 expression in the K1 PTC cell line so that we could investigate the effects of YAP1 on cancer cell proliferation. YAP1 overexpression enhanced PTC cell proliferation by activating ERK1/2 and AKT, and these effects were impaired by treating the cells with the MEK inhibitor U0126 or the AKT inhibitor GSK690693. Finally, YAP1 overexpression dramatically induced growth of tumors from PTC cells in a xenograft mouse model. These results suggest that YAP1 enhances cell proliferation in PTC, and thus may be a promising target in the treatment of PTC.

BRAF-activated LncRNA functions as a tumor suppressor in papillary thyroid cancer.

Long non-coding RNAs (lncRNAs) participate in cancer cell tumorigenesis, cell cycle control, migration, proliferation, apoptosis, metastasis and drug resistance. The BRAF-activated non-coding RNA (BANCR) functions as both an oncogene and a tumor suppressor. Here, we investigated BANCR's role in papillary thyroid carcinoma (PTC) by assessing BANCR levels in PTC and matched normal thyroid epithelial tissues from 92 patients using qRT-PCR. We also used lentiviral vectors to establish PTC cell lines to investigate the effects of BANCR overexpression on cancer cell proliferation, apoptosis, migration and invasion. Our results indicate BANCR levels are lower in PTC tumor tissues than control tissues. Decreased BANCR levels correlate with tumor size, the presence of multifocal lesions and advanced PTC stage. BANCR overexpression reduced PTC cell proliferation and promoted apoptosis, which inhibited metastasis. It also inactivated ERK1/2 and p38, and this effect was enhanced by treatment with the MEK inhibitor U0126. Finally, BANCR overexpression dramatically inhibited tumor growth from PTC cells in xenograft mouse models. These results suggest BANCR inhibits tumorigenesis in PTC and that BANCR levels may be used as a novel prognostic marker.

BRAF Mutations in Iranian Patients with Papillary Thyroid Carcinoma

Papillary thyroid cancer or papillary thyroid carcinoma (PTC) is the most common thyroid cancer. The fact that it occasionally occurs in women aged 30-40 years old suggests that genetic alterations are involved its genesis. Recently, activator mutations in BRAF gene have been relatively frequently discovered. In this study, we tested 63 DNA samples from PTC patients to identify the V600E mutation frequency in the Ahvaz population. DNA was isolated from formalin fixed paraffin-embedded (FFPE) PTC tumor tissues. Genotyping was performed by PCR-RFLP and confirmed by direct DNA sequencing of a subset of PCR products. PCR-RFLP data were reported as genotype frequencies and percentages. Forty nine out of 63 patients (77.8%) had a mutated heterozygote form while 14 (22.2%) showed normal genotype but none demonstrated a mutant homozygote genotype. The frequency of V600E mutation was significantly high in PTC patients. These findings support involvement of V600E mutations in PTC occurrence in Iran. Assessment of correlations between BRAF V600E mutations and papillary thyroid cancer progression needs to be performed.

Increased Expression of Vascular Endothelial Growth Factor C in Papillary Thyroid Carcinoma Correlates with Cervical Lymph Node Metastases

Despite recent studies showing that vascular endothelial growth factor C (VEGF-C) mRNA is up-regulated in papillary thyroid carcinoma (PTC), the role of VEGF-C in lymph node metastasis is still unclear. The aim of this study is to investigate the expression pattern of VEGF-C immunoreactive protein in PTC and its relationship with cervical lymph node metastasis. Tissue samples were obtained from 39 specimens of PTC (20 with and 19 without lymph node metastasis) as well as 20 benign thyroid nodules. Overexpression of the VEGF-C protein was evaluated by immunoblotting with specific anti-VEGF-C antibody in paired tumor and nontumor tissues from PTC. The data were compared with patients' clinicopathologic features and lymph node metastasis. Immunohistochemical staining was done on selected paraffin sections to determine cellular localization of VEGF-C and to assess flt-4 (or VEGFR-3)-positive vessel density in PTC lesions. Overexpression of VEGF-C was detected in 69% of the PTC and in 5% of the benign thyroid specimens. When comparing between the metastatic and nonmetastatic groups of PTC, a higher expression level of VEGF-C was detected in both the tumor (P = 0.004) and adjacent nontumor tissues (P = 0.011). Positive immunostaining for VEGF-C was confirmed in PTC tumor tissues and metastatic lymph nodes, which correlated with flt-4-positive vessel density in tumor and peritumor tissues. The increased expression of VEGF-C protein in PTC is associated with lymph node metastasis (P = 0.004) and lymphovascular permeation (P = 0.001) but is independent of other clinicopatholgic variables. The VEGF-C immunoreactive protein is overexpressed in PTC lesions, which correlates with lymph node metastases. VEGF-C expression may play a role in lymphangiogenesis of PTC and further study is necessary to evaluate the clinical application of VEGF-C as a molecular marker for tumor metastases to cervical lymph nodes.