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Background: The BRAF V600E mutation in papillary thyroid carcinoma (PTC) is particularly prevalent in Korea, and a considerable number of wild-type BRAF PTCs harbor RAS mutations. In addition, subsets of other genetic alterations clearly exist, but their prevalence in the Korean population has not been well studied. Recent increased insight into noninvasive encapsulated follicular variant PTC has prompted endocrine pathologists to reclassify this entity as "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP). This study analyzed the genetic alterations among the histologic variants of PTC, including NIFTP., Methods: Mutations of the BRAF and RAS genes and rearrangement of the RET/PTC1, NTRK1, and ALK genes using 769 preoperative fine-needle aspiration specimens and resected PTCs were analyzed., Results: Molecular alterations were found in 687 (89.3%) of 769 PTCs. BRAF V600E mutation (80.8%) was the most frequent alteration, followed by RAS mutation and RET/PTC1, NTRK1, and ALK rearrangements (5.6%, 2.1%, 0.4%, and 0%, respectively). The low prevalence of NTRK1 fusions and the absence of an ALK fusion detected in Korea may also be attributed to the higher prevalence of the BRAF V600E mutation. There were significant differences in the frequency of the genetic alterations among the histologic variants of PTC. The prevalence of NIFTP in PTC was 2.7%, and among the NIFTPs, 28.6% and 57.1% harbored BRAF and RAS mutations, respectively. Clinicopathologic factors and mutational profiles between NIFTP and encapsulated follicular variant PTC with capsular invasion group were not significantly different., Conclusions: Genetic alterations in PTC vary among its different histologic variants and seem to be different in each ethnic group.

The BRAF V600E mutation test has proven diagnostic value in thyroid fine-needle aspiration. The real-time polymerase chain reaction (RT-PCR) has recently been introduced as a new method for BRAF mutation detection. We performed BRAF V600E detection in 126 cases of thyroid fine-needle aspiration, using RT-PCR and pyrosequencing. BRAF V600E mutation was detected in 78 (61.9%) of 126 cases by RT-PCR and in 74 (57.8%) by pyrosequencing. Of the 98 papillary thyroid carcinoma samples, the BRAF V600E mutation was identified in 72 by RT-PCR and in 70 by pyrosequencing (sensitivities of 71.6% and 71.4%, respectively). Among 28 benign nodules, 6 false-positive cases were detected by RT-PCR, whereas 4 false-positive cases were detected by pyrosequencing (specificities of 78.6% and 85.7%, respectively). When analyzing 104 cases after excluding equivocal samples, pyrosequencing had a marginally higher specificity than RT-PCR (100% vs. 78.3%, P=0.074). After modifying the cut-off criteria, the low RT-PCR specificity improved to a similar or a slightly lower specificity compared with that of pyrosequencing. In the titration assay mixing the mutant DNA with the wild-type DNA in varying proportions, RT-PCR was sensitive enough to detect the mutation in a mixture containing 0.001% mutant DNA, whereas the limit of detection was 10% for pyrosequencing. In conclusion, compared with pyrosequencing, RT-PCR was more sensitive, faster, and more convenient, but less specific, for detecting the BRAF V600E mutation. A readjustment or modification of the interpretation criteria may be necessary to reduce false-positive RT-PCR results and improve the specificity while maintaining the sensitivity.

Genetic alterations of TERT and CTNNB1 have been documented in hepatocellular carcinoma. TERT promoter mutations are the earliest genetic events in the multistep process of hepatocarcinogenesis related to cirrhosis. However, analyses of TERT promoter and CTNNB1 mutations in hepatocellular carcinoma tumor samples have not been performed in the Korean population, where hepatitis B virus-related hepatocellular carcinoma is prevalent. In order to identify the role of TERT promoter and CTNNB1 mutations in the hepatocarcinogenesis and pathogenesis of recurrent hepatocellular carcinoma, we performed the sequence analyses in 140 hepatocellular nodules (including 107 hepatocellular carcinomas), and 8 pairs of matched primary and relapsed hepatocellular carcinomas. TERT promoter and CTNNB1 mutations were only observed in hepatocellular carcinomas but not in precursor lesions. Of 109 patients with hepatocellular carcinoma, 41 (39.0%) and 15 (14.6%) harbored TERT and CTNNB1 mutations, respectively. TERT promotermutations were significantly more frequent in hepatocellular carcinomas related to hepatitis C virus infection (5/6; 83.3%) compared to tumors of other etiologies (P = 0.001). In two cases, discordance in TERT promoter mutation status was observed between the primary and the corresponding recurrent hepatocellular carcinoma. The two patients with discordant cases had early relapses. In conclusion, we identified TERT promoter and CTNNB1 mutations as the most frequent somatic genetic alterations observed in hepatocellular carcinoma, indicating its pivotal role in hepatocarcinogenesis. Furthermore, we suggest the possibility of intratumoral genetic heterogeneity of TERT promoter mutations in hepatocellular carcinoma as indicated by the discordance in TERT promoter mutations between primary and corresponding recurrent hepatocellular carcinoma.

Objective: RAS mutations are the most common mutations in thyroid nodules with indeterminate cytology by fine-needle aspiration cytology (FNAC), and are mutually exclusive with BRAF mutations. However, the diagnostic utility of RAS mutation analysis is uncertain. We evaluated the diagnostic utility of RAS mutation analysis in indeterminate thyroid nodules., Design, Patients, and Measurements: A total of 155 thyroid nodules (90 benign and 65 indeterminate) negative for BRAF(V) (600E) mutations on FNAC were analysed for mutations in RAS codon 61 using pyrosequencing methods. We evaluated diagnostic accuracy of RAS mutation for predicting thyroid malignancy based on the surgical pathologic diagnosis., Results: Among the 65 BRAF(V) (600E) -negative indeterminate thyroid nodules identified by FNAC, 25 (38·5%) exhibited point mutations in RAS 61 consisting of 18 NRAS 61 (72%), and 7 HRAS 61 (28%) mutations. In contrast, only five of 90 (5·6%) nodules with benign cytology had RAS mutations. Only two of 25 (8·0%) RAS 61(+) indeterminate nodules exhibited malignant ultrasonographic features. Of the 15 patients with RAS 61(+) -indeterminate nodules who underwent thyroid surgery, 14 (93·3%) were diagnosed as malignant, including 13 follicular variant of papillary thyroid carcinomas (FVPTC), and one follicular thyroid carcinoma (FTC). The average tumour size was 1·79 ± 0·62 cm. Multifocality was seen in 28·6% of cases, with 7·1% exhibiting extrathyroidal extension; no lymph node or distant metastases were evident. Based on the surgical pathologic diagnosis results, preoperative RAS 61 mutation analysis on FNAC exhibited 93·3% sensitivity, 75·0% specificity, 93·3% positive predictive value, 75·0% negative predictive value and 89·5% diagnostic accuracy for predicting malignancies., Conclusion: Our results suggest that RAS mutation analysis holds great promise as a preoperative diagnostic tool for predicting FVPTC in cytologically and sonographically indeterminate nodules negative for BRAF mutations., (© 2014 John Wiley & Sons Ltd.)

Follicular variants of papillary thyroid carcinoma (FVPTC), particularly the encapsulated subtype, often cause a diagnostic dilemma. Therefore, many FVPTCs are interpreted as "indeterminate" in preoperative fine-needle aspiration (FNA). The aim of this study was to analyze the genotypic changes in BRAF codons 600 and 601, as well as the N, H, and KRAS codons 12, 13, and 61 in FVPTCs and investigate the usefulness of preoperative BRAF and RAS mutation analysis as an adjunct diagnostic tool along with routine FNA. Surgically resected thyroid nodules were reviewed to establish the histological diagnosis of FVPTC. All preoperative FNA diagnoses were categorized according to the Bethesda Reporting System. Mutations in BRAF codons 600 and 601, and N, H, KRAS codons 12, 13, and 61 were analyzed by pyrosequencing. Of 132 cases, 81 (61.4 %) had a point mutation in one of the BRAF V600E, BRAF K601E, or RAS oncogenes; BRAF V600E in 43(32.6 %), BRAF K601E in three (2.3 %), and RAS in 35 (26.5 %) cases. All mutations were mutually exclusive. Of 78 cases with an FNA indeterminate category diagnosis, 51 (65.4 %) were positive for mutations: 24 for BRAF V600E, 3 for BRAF K601E, and 24 for the RAS gene. The KRAS mutation was more frequently found than the HRAS mutation, comprising 22.9 % of the RAS mutations, and all KRAS mutations were located at codon 61. This study demonstrated that either BRAF or RAS mutations were present in two thirds of FVPTCs and these mutations were mutually exclusive.

Context: Several ultrasonographic (US) features of thyroid nodules have been reported to predict malignancy. The BRAF(V600E) mutation is a useful diagnostic marker for differentiating papillary thyroid carcinoma from benign thyroid nodules, especially in BRAF(V600E) -prevalent populations such as in Korea., Objective: To evaluate the association of BRAF(V600E) mutation with US features of thyroid nodules in predicting the malignancy of thyroid nodules in Korean patients., Design: A total of 991 thyroid nodules from 823 patients in fine-needle aspiration biopsy (FNAB) specimens were investigated. The relationship between US features and the presence of BRAF(V600E) mutation by pyrosequencing method was prospectively analysed., Results: The BRAF(V600E) mutation was associated with the following US features: solid composition [odds ratio (OR) 20·338; 95% confidence interval (CI): 4·952-83·532; P < 0·001], marked hypoechogenicity (OR 30·744; 95% CI: 15·951-59·255; P < 0·001), irregular margin (OR 9·889; 95% CI: 7·005-13·859; P < 0·001), taller-than-wide shape (OR 6·031; 95% CI: 4·343-8·376; P < 0·001) and the presence of microcalcifications (OR 6·664; 95% CI: 4·604-9·648; P < 0·001). The BRAF(V600E) mutation with malignant US features in FNAB enhanced the diagnostic accuracy compared with cytologic diagnosis alone (94·3%vs 69·7%)., Conclusion: The BRAF(V600E) mutation is significantly associated with malignant US features, such as solid composition, marked hypoechogenicity, irregular margin, taller-than-wide shape and the presence of microcalcifications. The application of BRAF(V600E) mutation analysis in US-guided FNAB can improve the diagnostic accuracy of thyroid nodules., (© 2011 Blackwell Publishing Ltd.)

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.

With various methods, BRAF mutations have been detected in 73.4% to 87.1% of papillary thyroid carcinomas (PTCs) in Korea. We assessed the ability of allele-specific polymerase chain reaction using a dual priming oligonucleotide system, compared with direct sequencing and pyrosequencing, to detect BRAF mutations in fine-needle aspiration specimens from 85 patients undergoing thyroidectomy. Final pathologic diagnoses were 55 malignant lesions and 30 benign lesions. We detected BRAF mutations in 47 (90%) of 52 PTCs by at least 1 method. The sensitivity of the dual priming oligonucleotide system (88.5%) was slightly higher than that of direct sequencing (82.7%) and pyrosequencing (86.5%). The specificity and positive predictive value of all 3 methods were 100%. The dual priming oligonucleotide system is a simple, rapid, and reliable method for detecting BRAF mutations. This method may be a useful adjunct tool to improve the preoperative diagnostic accuracy of PTC in fine-needle aspiration biopsy specimens.

Objective: Inactivation of p53, either through mutation or interaction with human papillomavirus (HPV) E6 oncoprotein, is a characteristic feature of cervical carcinoma cell lines that have been previously studied. To elucidate the role of p53 in the carcinogenesis of Korean cervical carcinomas, 27 HPV-positive and 13 HPV-negative cervical carcinomas were studied in order to evaluate the status of the p53 gene., Study Design: The HPV status was ascertained by polymerase chain reaction (PCR) amplification using consensus primers designed from the E6 and E7 open reading frames (ORFs). The p53 mutation status was analyzed by direct sequencing of the PCR product in highly conserved exons 5-8., Results: There was no significant difference in the frequency of the p53 mutation between the HPV-positive and negative cases. All three mutations in the HPV-positive cases were associated with intermediate-risk viruses. The average age of the patients with the p53 mutation was 14 years older than that of patients without the p53 mutation., Conclusion: p53 mutations are higher in the so called intermediate-risk HPV positive than HPV 16 or 18 positive cervical carcinomas.