Establishment and characterization of cell lines from three human thyroid carcinomas: responses to all-trans-retinoic acid and mutations in the BRAF gene

Morphologic and genomic changes of thyroid cancer cell lines exposed to conditions of simulated microgravity

Microgravity in space impacts human health. In particular, thyroid cancer, which has a high incidence rate, has been the subject of numerous studies with respect to microgravity. However, most studies have focused on Western follicular thyroid cancer cell lines, while data regarding the effects of microgravity on Asian cell lines are lacking. Therefore, we aimed to investigate the effect of simulated ground-based microgravity on two Korean thyroid cancer cell lines, namely SNU-790 and SNU-80. We found that both cell lines formed multicellular spheroids under simulated microgravity. Gene expression analysis revealed that in SNU-790 cells, histone-related genes were upregulated and microRNA-related genes were downregulated. Meanwhile, in SNU-80 cells, genes related to the cellular response to hypoxia were downregulated. These findings contribute to a better understanding of the effects of microgravity on thyroid cancer cells. Further validation studies and clinical significance analyses are needed to fully understand the implications of these findings.

Synthetic Retinoid Kills Drug-Resistant Cancer Stem Cells via Inducing RARγ-Translocation-Mediated Tension Reduction and Chromatin Decondensation

A recently developed synthetic retinoid abrogates proliferation and induces apoptosis of drug-resistant malignant-cancer-stem-cell-like cells. However, the underlying mechanisms of how the synthetic retinoid induces cancer-stem-cell-like cell tumor-repopulating cell (TRC) apoptosis are elusive. Here, it is shown that although the retinoid and conventional anticancer drugs cisplatin, all-trans retinoic acid, and tazarotene all inhibit cytoskeletal tension and decondense chromatin prior to inducing TRC apoptosis, half-maximal inhibitory concentration of the retinoid is 20-fold lower than those anticancer drugs. The synthetic retinoid induces retinoic acid receptor gamma (RARγ) translocation from the nucleus to the cytoplasm, leading to reduced RARγ binding to Cdc42 promoter and Cdc42 downregulation, which decreases filamentous-actin (F-actin) and inhibits cytoskeletal tension. Elevating F-actin or upregulating histone 3 lysine 9 trimethylation decreases retinoid-induced DNA damage and apoptosis of TRCs. The combinatorial treatment with a chromatin decondensation molecule and the retinoid inhibits tumor metastasis in mice more effectively than the synthetic retinoid alone. These findings suggest a strategy of lowering cell tension and decondensing chromatin to enhance DNA damage to abrogate metastasis of cancer-stem-cell-like cells with high efficacy.

Selective inhibition of V600E-mutant BRAF gene induces apoptosis in thyroid carcinoma cell lines

Purpose

Papillary thyroid cancer (PTC) has a high incidence of BRAF^V600E mutation. The purpose of this study was to evaluate the potential relationship between thyroiditis and BRAF^V600E mutation status in patients with PTC. We investigated how a selective inhibitor of BRAF^V600E PLX4032 affects the proliferation and inflammatory cytokine levels of thyroid cancer.

Methods

Two thyroid cancer cell lines TPC1 and 8505C were treated with PLX4032, an analysis was done on cell growth, cell cycle, the degree of apoptosis, and levels of inflammatory cytokines. To identify the functional links of BRAF, we used the STRING database.

Results

Docking results illustrated PLX4032 blocked the kinase activity by exclusively binding on the serine/threonine kinase domain. STRING results indicated BRAF is functionally linked to mitogen-activated protein kinase. Both cell lines showed a dose-dependent reduction in growth rate but had a different half maximal inhibitory concentration value for PLX4032. The reaction to PLX4032 was more sensitive in the 8505C cells than in the TPC1 cells. PLX4032 induced a G2/M phase arrest in the TPC1 cells and G0/G1 in the 8505C cells. PLX4032 induced apoptosis only in the 8505C cells. With PLX4032, the TPC1 cells showed decreased levels of vascular endothelial growth factor, granulocyte-macrophage colony-stimulating factor, chemokine (C-C motif) ligand 2/monocyte chemoattractant protein 1, whereas the 8505C cells showed significantly decreased levels of IL-8, serpin E1/plasminogen activator inhibitor-1, and matrix metalloproteinase (MMP)-3.

Conclusion

PLX4032 was cytotoxic in both TPC1 and 8505C cells and induced apoptosis. In the 8505C cells, inflammatory cytokines such as IL-8 and MMP-3 were down-regulated. These findings suggest the possibility that the BRAF^V600E mutation needs to target inflammatory signaling pathways in the treatment of thyroid cancer.

The Significance of TROP2 Expression in Predicting BRAF Mutations in Papillary Thyroid Carcinoma

BACKGROUND

Trophoblast antigen 2 (TROP2) is a human trophoblast cell-surface glycoprotein that is overexpressed in several types of epithelial cancers, and is suggested to be associated with an unfavorable prognosis. BRAF mutations are the most common genetic alteration in papillary thyroid carcinoma (PTC). We evaluated the correlation between TROP2 expression and BRAF mutation in PTC.

METHODS

First, we carried out pyrosequencing for BRAF mutations and immunohistochemistry for TROP2 expression with a tissue microarray consisting of 52 PTC cases. Membranous staining in at least 5% of tumor cells was designated as positive staining and we analyzed the relationship between TROP2 expression and diverse clinicopathological factors, including BRAF mutation. Second, we tested TROP2 mRNA expression in three thyroid cancer cell lines with BRAF mutations (BCPAP, SNU790, and 8505C) and a normal thyroid cell line. Additionally, we checked TROP2 protein levels in a normal thyroid cell line after introduction of the BRAF V600E mutation.

RESULTS

In this study, 21 of 26 cases with BRAF mutation showed TROP2 immunoreactivity, whereas all 26 cases without BRAF mutation showed no immunoreactivity for TROP2 with a statistically significant difference (p<.001). Upregulation of TROP2 mRNA was observed in all three thyroid cancer cell lines, but not in the normal thyroid cell line. Interestingly, however, the TROP2 expression was increased in the normal thyroid cell line after introduction of the BRAF V600E mutation.

CONCLUSIONS

Based on these results, we concluded that TROP2 expression is significantly associated with BRAF mutation and that TROP2 immunohistochemistry could be used for predicting BRAF mutations or diagnosing papillary thyroid carcinoma.

Role of laminin 332 in lymph node metastasis of papillary thyroid carcinoma

OBJECTIVE

The invasiveness of papillary thyroid carcinoma (PTC), including the occurrence of cervical lymph node metastasis, is the main determining factors contributing to recurrence and poor prognosis. Laminin 332 is a glycoprotein involved in cell migration and cancer cell invasion into surrounding tissues and is therefore related to poor prognosis in many cancers. Here, we investigated the expression and role of laminin 332 in PTC and examine the possibility that laminin 332 could be involved in the invasiveness of PTC.

METHODS

Laminin 332 expression was determined by immunohistochemical staining in all 40 patients. The correlations between laminin 332 expression and clinical factors were investigated. We examined the expression of the laminin 332 γ2 chain using reverse transcription polymerase chain reaction and western blotting in PTC cells and determined the relationship between the expression of laminin 332 and the invasiveness of these cell lines using cell invasion assays.

RESULTS

Laminin 332 was expressed specifically within tumor tissue. The frequency of laminin 332 γ2 chain expression was significantly correlated with cervical lymph node metastasis (​p=0.003). Invasiveness increased as the expression of laminin 332 γ2 increased in the tested PTC cell lines.

CONCLUSION

Laminin 332 expression may be a useful marker for predicting lymph node metastasis in papillary thyroid carcinoma, and could increase the ability of cancer cells to invade, which would influence the prognosis of patients with PTC.

nc886, a non-coding RNA and suppressor of PKR, exerts an oncogenic function in thyroid cancer

nc886 is a recently identified cellular non-coding RNA and its depletion leads to acute cell death via PKR (Protein Kinase RNA-activated) activation. nc886 expression is increased in some malignancies, but silenced in others. However, the precise role of nc886/PKR is controversial: is it a tumor suppressor or an oncogene? In this study, we have clarified the role of nc886 in thyroid cancer by sequentially generating PKR knockout (KO) and PKR/nc886 double KO cell lines from Nthy-ori 3-1, a partially transformed thyroid cell line. Compared to the wildtype, PKR KO alone does not exhibit any significant phenotypic changes. However, nc886 KO cells are less proliferative, migratory, and invasive than their parental PKR KO cells. Importantly, the requirement of nc886 in tumor phenotypes is totally independent of PKR. In our microarray data, nc886 KO suppresses some genes whose elevated expression is associated with poor survival confirmed by data from total of 505 thyroid cancer patients in the Caner Genome Atlas project. Also, the nc886 expression level tends to be elevated and in more aggressively metastatic tumor specimens from thyroid cancer patients. In summary, we have discovered nc886's tumor-promoting role in thyroid cancer which has been concealed by the PKR-mediated acute cell death.

Update: the status of clinical trials with kinase inhibitors in thyroid cancer

CONTEXT

Thyroid cancer is usually cured by timely thyroidectomy; however, the treatment of patients with advanced disease is challenging because their tumors are mostly unresponsive to conventional therapies. Recently, the malignancy has attracted much interest for two reasons: the dramatic increase in its incidence over the last three decades, and the discovery of the genetic mutations or chromosomal rearrangements causing most histological types of thyroid cancer.

OBJECTIVE

This update reviews the molecular genetics of thyroid cancer and the clinical trials evaluating kinase inhibitors (KIs) in patients with locally advanced or metastatic disease. The update also reviews studies in other malignancies, which have identified mechanisms of efficacy, and also resistance, to specific KIs. This information has been critical both to the development of effective second-generation drugs and to the design of combinatorial therapeutic regimens. Finally, the update addresses the major challenges facing clinicians who seek to develop more effective therapy for patients with thyroid cancer.

RESULTS

PubMed was searched from January 2000 to November 2013 using the following terms: thyroid cancer, treatment of thyroid cancer, clinical trials in thyroid cancer, small molecule therapeutics, kinase inhibitors, and next generation sequencing.

CONCLUSIONS

A new era in cancer therapy has emerged based on the introduction of KIs for the treatment of patients with liquid and solid organ malignancies. Patients with thyroid cancer have benefited from this advance and will continue to do so with the development of drugs having greater specificity and with the implementation of clinical trials of combined therapeutics to overcome drug resistance.

Functional analysis of three novel cell lines derived from human papillary thyroid carcinomas with three different clinical courses

Papillary thyroid carcinoma (PTC) is the most frequent thyroid carcinoma. PTC cell lines have been of considerable value in studying aspects of thyroid cancer, such as gene expression, cell proliferation, and differentiation. Here we report three novel PTC lines established from three patients with different backgrounds. Case 1 was a 38-year-old woman with PTC in the right thyroid lobe, with no metastasis. The cell line was established from the resection sample and named D-PTC. The cell line consisted of epithelial cells with few lysosomes and showed a pavement structure and follicular formation at confluency. There was a little pilling up. The secretion of free thyroxin (fT4) and thyroglobulin (Tg) was increased by TSH, or GH and IGF-I treatment. Case 2 was a 22-year-old woman with PTC initially in the right thyroid lobe, but 4 years after the right lobe resection, PTC metastasis was observed in left lobe. The cell line was established from a sample of the second resection and named UD-PTC. This cell line consisted of small epithelial cells with evident lysosomes and exhibited floating cell clusters. The secretion of fT4 and Tg was slightly increased by TSH, or GH and IGF-I treatment. Case 3 was an 85-year-old man with PTC and with acromegaly. Metastasis was observed at cervical lymph nodes. The cell line was derived from the metastasis region and named A-PTC. This cell line consisted of small epithelial cells and many lysosomes. The cells frequently showed pilling up. The secretion of fT4 and Tg was significantly increased by GH and IGF-I treatment. We have established three PTC cell lines with substantial variation in their phenotype. The cell lines may be useful for thyroid cancer research.

Establishment and characterization of seven human breast cancer cell lines including two triple-negative cell lines

Permanently growing cell lines can be invaluable because of their usefulness in a variety of experimental situations. We report the characteristics of seven cell lines designated, SNU-306, SNU-334, SNU-1528, SNU-1553, SNU-1581, SNU-1958 and SNU-2372, which were established from three primary carcinomas, two pleural effusion, one pericardial effusion and one ascitic fluid samples obtained from seven Korean breast carcinoma patients. The histopathology of the primary tumors and their in vitro growth characteristics are described. DNA fingerprinting analysis and genetic alterations in the p53 and EGFR genes were conducted. The expression levels of the ER-α, PR, C-erbB2, E-cadherin, COX-2, MDR and MXR genes were investigated and sensitivity to anticancer drugs was screened. Growth was as adherent cells (four cell lines), floating aggregates (one cell line) and both (two cell lines). All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis using 18 microsatellite markers. Estrogen receptor (ER) mRNA was highly expressed in five cell lines and low or undetectable in SNU-1958 and SNU-2372. Progesterone receptor (PR) mRNA was expressed only in the SNU-306. SNU-1958 and SNU-2372 were hormone receptor-negative and C-erbB2-negative (triple-negative). SNU-1528 had an in-frame deletion of 42 base pairs of p53 gene and showed over 20-fold resistance for taxol compared to the other cell lines. There were no mutation in the EGFR gene; COX-2 was expressed in four cell lines and MXR was expressed in two cell lines. These well-characterized seven breast cancer cell lines, which include two triple-negative cell lines, will be useful for the study of breast cancer biology.

Dickkopf-1 inhibits thyroid cancer cell survival and migration through regulation of β-catenin/E-cadherin signaling

Wnt/β-catenin signaling plays a role in tumorigenesis of human papillary thyroid cancer (PTC). Dickkopf-1 (Dkk-1) is an inhibitor of Wnt/β-catenin signaling. We investigated the therapeutic potential of Dkk-1 in human PTC cell lines, SNU-790, B-CPAP, and BHP10-3. Dkk-1 reversed the aberrant expression of β-catenin from nucleus to membrane and inhibited basal levels of TCF/LEF-dependent transcriptional activities. Furthermore, Dkk-1 inhibited cell viability in a dose-dependent manner and adenoviral transduction of constitutively active β-catenin blocked these effects, thus suggesting that the Dkk-1 anti-tumoral effect is mediated by Wnt/β-catenin signaling. Bromodeoxyuridine assay showed minimal effects of Dkk-1 on cell proliferation. Flow cytometric analysis with Annexin V staining showed marked induction of cell apoptosis by Dkk-1 treatment. Dkk-1 also restored the loss of membranous E-cadherin expression with consequent inhibition of cell migration and invasion. In conclusion, Dkk-1 inhibited the survival and migration of human PTC cells by regulating Wnt/β-catenin signaling and E-cadherin expression.

The potential mechanism for the different expressions of gelatinases induced by all-trans retinoic acid in different cells

Gelatinases include matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). The increased expressions of gelatinases are implicated in the pathogenesis of cell injury and cell death. All-trans retinoic acid (ATRA) is an import biological agent which can regulate the expressions of gelatinases and take part in cell injury and cell death. ATRA exerts its biological effect by the high-affinity binding to retinoic acid receptors (RARs). The RARs consist of three isoforms: RAR-α, RAR-β and RAR-γ. However, it is interesting that the effect of ATRA on the expressions of gelatinases is different in different cells. There is no report to explore the possible mechanism for it at present. In this context, we review the published reports and draw a hypothesis that: (i) The distributions of RARs isoforms are different in different cells; (ii) ATRA activates the different RARs isoforms in different cells; (iii) The roles of different RARs isoforms for regulating the expression of MMP-2 or MMP-9 are different in different cells. So, ATRA takes a different function on the expressions of MMP-2 and MMP-9 in different cells. Once the potential strategy can be successfully confirmed, it would be prone to comprehend why the ATRA regulates the different expressions of gelatinases in different cells.

Pyrosequencing cut-off value identifying BRAFV600E mutation in fine needle aspiration samples of thyroid nodules

CONTEXT

Recently, tremendous efforts have been made towards the development of sensitive techniques to detect the BRAF(V600E) mutation in fine needle aspiration biopsy (FNAB) samples. However, newly developed quantitative and semi-quantitative methods, such as dual-priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR), have the potential to generate false-positive (FP) results.

OBJECTIVES

To eliminate the possibility of FP results, we generated a receiver operating characteristic (ROC) curve to investigate the diagnostic accuracy of pyrosequencing using quantitative data.

DESIGN

Cytological diagnoses of 983 thyroid nodules were made according to the Bethesda System 2007. The BRAF(V600E) mutation was analysed by pyrosequencing, and statistical analyses were performed.

RESULTS

Of the 983 nodules, 902 were adopted to evaluate the diagnostic value of pyrosequencing. The number of pathologically confirmed malignancies was 192, of which 182 were papillary thyroid cancer (PTC). By generating an ROC curve, we defined the optimal cut-off value of the mutant allele peak as 5·95% (area under the curve, 0·849; sensitivity, 0·55; 1-specificity, 0). When we applied this selective cut-off value, the number of PTCs positive for BRAF(V600E) was 99 (54·4% of the total number of PTCs). With cytology alone, the diagnostic sensitivity and specificity of detecting malignancy were 71·2% and 100%, respectively. Pyrosequencing improved the diagnostic sensitivity from 71·2% to 78·5% (McNemar's test, P < 0·001), without any change in the diagnostic specificity. When 'suspicious for malignancy' was considered a positive cytological outcome, pyrosequencing increased the diagnostic sensitivity of cytology from 95·8% to 96·9%; however, this improvement did not show statistical significance (McNemar's test, P > 0·05).

CONCLUSIONS

Pyrosequencing is an effective method for detecting the BRAF(V600E) mutation in FNAB samples. By allowing the optimal cut-off value to be determined, pyrosequencing improves the diagnostic sensitivity while eliminating the possibility of FP results.

Surgical results of thyroid nodules according to a management guideline based on the BRAF(V600E) mutation status

CONTEXT

In Korea, where PTC comprises about 90-95% of the reported thyroid cancers, the prevalence of BRAF(V600E) mutation in papillary thyroid carcinoma (PTC) is above 80%.

OBJECTIVE

We analyzed the surgical result according to a management guideline based on the BRAF(V600E) mutation status of thyroid nodules.

DESIGN

A total of 865 thyroid nodules were prospectively analyzed for their cytology and BRAF(V600E) mutation status by pyrosequencing. For the patients who had a diagnosis of atypical cells of undetermined significance (ACUS), we recommended surgery when there was positivity for BRAF(V600E) mutation or the nodules were clinically suspicious.

RESULTS

Among 865 cases, 504, 141, 54, 140, 10, and 16 were diagnosed as benign, ACUS, suspicious for malignancy, malignant, suspicious for follicular neoplasm, and nondiagnostic, respectively. None of the 504 benign, 45 (31.9%) of the 141 ACUS, 46 (85.2%) of the 54 suspicious for malignancy, 129 (92.1%) of the 140 malignant, and one (10%) of the 10 suspicious for follicular neoplasm cases showed BRAF(V600E) mutation. Surgery was recommended to all 45 patients with BRAF(V600E) mutation-positive ACUS nodules; among them, 30 patients underwent surgery, 29 had PTC, and one had nodular hyperplasia. All the patients diagnosed as suspicious for malignancy or malignant were advised to undergo an operation, and they turned out to have PTCs regardless of their BRAF(V600E) mutation status.

CONCLUSIONS

We found that performing BRAF(V600E) mutation analysis on the fine-needle aspiration biopsy specimens was of great help to make a therapeutic decision for thyroid nodules when the fine-needle aspiration biopsy results were equivocal.

Establishment and characterization of six human lung cancer cell lines: EGFR, p53 gene mutations and expressions of drug sensitivity genes

BACKGROUND

Six human lung cancer cell lines (SNU-371, SNU-963, SNU-1327, SNU-1330, SNU-2292 and SNU-2315) were newly established through primary cell cultures. These cell lines were derived from a pulmonary blastoma, a small cell lung cancer, three adenocarcinomas and a squamous cell carcinoma of the lung of six Korean lung cancer patients.

METHODS

The histopathology of the primary tumors and their in vitro growth characteristics were described. DNA fingerprinting analysis and genetic alterations in the p53, β-catenin, TGFβRII, K-ras and EGFR genes were conducted. mRNA expressions levels of E-cadherin, COX-2, MDR1, MXR, CGA, synatophysin and TTF1 genes were investigated and sensitivity to anticancer drugs was screened.

RESULTS

Five cell lines grew as adherent cells and one cell line grew as floating aggregates. All lines were free of mycoplasma or bacteria and were proven unique by DNA fingerprinting analysis. A significant polymorphism at codon 72 (Arg to Pro) of the p53 gene was found in one line (SNU-1327) and a mutation at codon 176 was found in SNU-2292. No mutations in the K-ras, β-catenin and TGF-βRII genes were observed. E-cadherin was not expressed in SNU-371 and COX-2 was overexpressed in SNU-1330, SNU-2292 and SNU-2315 cell lines. MDR1 was overexpressed in SNU-371 and SNU-2292 cell lines and MXR was overexpressed in SNU-1327 cell line. Interestingly, the SNU-371 cell line derived from a pulmonary blastoma and which overexpressed MDR1 displayed cross resistance for several anticancer drugs. Neuroendocrine markers, chromogranin A and synaptophysin, were overexpressed in the small cell lung cancer cell line, SNU-963 and thyroid transcription factor-1 was also over expressed in this cell line. Two mutations (p.Glu746_Ser752delinsVal and p.Glu746_Ala750del) in exon 19 of EGFR were found in SNU-1330 and SNU-2315 cell lines, respectively.

CONCLUSION

These well-characterized lung cancer cell lines may be useful tools for investigations of the biological characteristics of lung cancers, particularly for investigations related to mutations of EGFR.

Retinoic acid receptor and retinoid X receptor subtype expression for the differential diagnosis of thyroid neoplasms

BACKGROUND

Although differential expression of retinoic acid receptor (RAR) subtypes between benign and malignant thyroid tissues has been described, their diagnostic value has not been reported.

AIM

To investigate the diagnostic accuracy of RAR and retinoid X receptor (RXR) subtype protein expression for the differential diagnosis of thyroid neoplasms.

METHODS

We used a tissue array containing 93 benign thyroid tissues (normal thyroid, multinodular goiter, and follicular adenoma (FA)) and 77 thyroid carcinomas (papillary thyroid carcinoma (PTC), follicular thyroid carcinoma, and follicular variant of PTC (FVPTC)). Immunostaining was done for RAR and RXR subtypes. Staining was analyzed semiquantitatively based on receiver operating curve analyses and using hierarchical cluster analysis.

RESULTS

We found increased expression of cytoplasmic (c) RARA, cRARG, cRXRB and decreased expression of nuclear (n) RARB, nRARG, and nRXRA in thyroid carcinomas compared with benign tissues. We found three proteins differently expressed between FA and FTC and five proteins differentially expressed between FA and FVPTC, with high diagnostic accuracies. Using cluster analysis, the combination of negative staining of membranous RXRB and positive staining for cRXRB had a high positive predictive value (98%) for malignant thyroid disease, whereas the combination of positive nRXRA and negative cRXRB staining had a high predictive value (91%) for benign thyroid lesions.

CONCLUSION

We conclude that differences in RAR and RXR subtype protein expression may be valuable for the differential diagnosis of thyroid neoplasms. The results of this study and especially the value of cluster analysis have to be confirmed in subsequent studies.

Clinical and pathological features and the BRAF(V600E) mutation in patients with papillary thyroid carcinoma with and without concurrent Hashimoto thyroiditis

BACKGROUND

It has been reported that patients with papillary thyroid carcinoma (PTC) have a high incidence of background Hashimoto thyroiditis (HT); however, the linkage of HT to PTC is controversial. Recent studies have shown that the prevalence of activating point mutations in BRAFV600E is much higher (73-86%) in Korea than in Western countries (29-69%), and associated with a poor prognosis in PTC. The purpose of the present study was to investigate the frequency of the BRAFV600E mutation in PTC with and without HT, and to determine clinical and pathological features that were associated with concomitant HT and PTC.

METHODS

Fine-needle aspiration slides from 101 patients with surgically confirmed PTC were studied. The DNA was extracted from the atypical cells that were scraped from slides. It was then analyzed for the BRAFV600E mutation by pyrosequencing. In addition, the presence of background HT in surgical specimens and other clinical and pathological features of the patients were characterized.

RESULTS

HT was present in 37 (36.6%) of the patients. The BRAFV600E mutation was present in 27 (72.9%) of patients with HT but was present in 61 (95.3%) of patients without HT ( p#0.01). The inverse correlation of concurrent HT with the BRAFV600E mutation was significant for both males and females ( p < 0.01). The presence of background HT was not associated with tumor size, extrathyroidal invasion, lymph node (LN) metastasis, or tumor stage. The patients were younger in the group without background HT (44.1 +/- 13.2 vs. 49.8 +/- 13.9, p 1/40.05). The BRAFV600E mutation was present in 88 (87.1%) of the 101 patients with PTC. The presence of the BRAFV600E mutation was significantly associated with LN metastasis ( p < 0.02; odds ratio, 6.24; 95% confidence interval, 1.51-25.79).

CONCLUSION

In Korean patients with PTC, the BRAFV600E mutation is associated with a lower frequency of background HT and a high frequency of LN metastasis.