BRAF mutations are associated with some histological types of papillary thyroid carcinoma

Mutations in the BRAF gene have recently been detected in a wide range of neoplastic lesions with a particularly high prevalence in melanoma and papillary thyroid carcinoma (PTC). The hot-spot mutation BRAF(V599E) is frequently detected in PTC (36-69%), in contrast to its absence in other benign or malignant thyroid lesions. In order to unravel whether there is any association between the occurrence of the BRAF mutation and the histological pattern of PTC, in this study a previous series of 50 PTCs was extended to 134 cases, including ten cases of PTC-related entities-hyalinizing trabecular tumour (HTT) and mucoepidermoid carcinoma (MEC). Using PCR/SSCP and sequencing, the BRAF(V599E) mutation was detected in 45 of the 124 PTCs (36%). No mutations were detected in any case of HTT and MEC. BRAF(V599E) was present in 75% of Warthin-like PTCs and 53% of conventional PTCs, whereas no BRAF(V599E) mutations were detected in any of the 32 cases of the follicular variant of PTC. BRAF(V599E) was also detected in 6 of 11 cases of the oncocytic variant of PTC that displayed a papillary or mixed follicular-papillary growth pattern and in none of the four oncocytic PTCs with a follicular growth pattern. A distinct mutation in BRAF (codon K600E) was detected in three cases of the follicular variant of PTC. This study has confirmed the high prevalence of BRAF(V599E) in PTC and has shown that the mutation is almost exclusively seen in PTC with a papillary or mixed follicular-papillary growth pattern, regardless of the cytological features of the neoplastic cells. The results support the existence of an oncocytic variant of PTC that should be separated from the oncocytic variant of follicular carcinoma and suggest that the follicular variant of PTC may be genetically different from conventional PTC.     

BRAF mutation analysis in fine needle aspiration (FNA) cytology of the thyroid.

BRAF mutations have been detected in 30% to 80% of papillary thyroid carcinomas (PTC). Several detection methods for BRAF mutation have been reported, but a direct comparison between different assay methods has not been previously reported. In this study, we examined the diagnostic utility of BRAF (T1799A) mutation in 71 cases of thyroid fine needle aspiration specimens using 4 different methods, including direct sequencing, Colorimetric Mutector Assay, real-time LightCycler polymerase chain reaction (LC PCR) with fluorescence resonance energy transfer probes, and an allele-specific LC PCR with CYBR green 1. BRAF mutation was detected in 31 of 58 cases of PTC, but not in 13 cases of non-PTC lesions. The 4 assay methods used in this study were sensitive, reliable, and comparable with each other (100% of specificity and 53.5% of sensitivity). PTC harboring BRAF mutation had higher extrathyroidal invasion and/or lymph node metastasis than PTC with wild-type BRAF. BRAF mutation analysis should be useful for the clinical diagnosis of PTC in cases of indeterminate fine needle aspiration specimen, because of the high degree of specificity. Our results indicate that there is similar sensitivity for the four detection methods. However, the allele-specific LC PCR with CYBR green 1 method is most rapid, easier to perform, and least expensive technique, and it can be readily performed in most molecular diagnostic laboratories.     

BRAF mutation and AKAP9 expression in sporadic papillary thyroid carcinomas

AIM: We aimed to determine the BRAF mutation and AKAP9 expression in papillary thyroid carcinomas (PTCs). METHODS AND RESULTS: In this study, we analysed 100 sporadic PTC specimens and we detected mutation in 62.2% of the conventional type PTCs (51/82), in 50% of the follicular variant type PTCs (3/6), in 50% of the diffuse sclerosing variant type PTCs (1/2), and in 30% of the microcarcinomas (3/10). All mutations involved a T-->A transversion at the nucleotide 1796. The cases with BRAF mutation were significantly associated with extrathyroidal extension. We also evaluated the expression of AKAP9 protein by immunohistochemistry. The AKAP9 protein was seen as a single perinuclear dot in all the PTCs. Therefore, 58% of the specimens harboured the BRAF mutation and no case had AKAP9-BRAF fusion in the sporadic PTCs. CONCLUSION: Our results suggest that the BRAF mutation can be a useful diagnostic and prognostic marker and a target for exploring novel cancer therapies to treat PTCs. AKAP9-BRAF fusion may be a very rare event in sporadic PTCs.     

A Novel Complex BRAF Mutation Detected in a Solid Variant of Papillary Thyroid Carcinoma

BRAF gene mutations are identified in about 45% of papillary thyroid carcinomas (PTC) and represent the most common genetic event in this tumor. Here, we report a case of PTC, solid variant, with a complex BRAF mutation that involves one nucleotide substitution, C1796T, and a CTT triplet insertion, 1798_1799insCTT, located on the same allele. This mutation leads to the replacement of a threonine with an isoleucine, T599I, and replacement of a valine with an alanine and a leucine, V600delinsAL. This mutation was identified both in the preoperative fine needle aspirate sample and in the surgical specimen after total thyroidectomy. Other rare BRAF mutations in PTC are reviewed.     

Molecular genetic study comparing follicular variant versus classic papillary thyroid carcinomas: association of N-ras mutation in codon 61 with follicular variant

Although the follicular variant of papillary thyroid carcinoma (FVPTC) has been classified as a papillary cancer based on nuclear features, its follicular growth pattern and potential for hematogenous spread are more characteristic of follicular carcinoma. To gain insight into the biologic nature of FVPTC, we compared genetic alterations characteristic of papillary and follicular thyroid carcinomas in 24 FVPTCs and 26 classic PTC (CPTCs). In FVPTCs, we observed ras mutation in 6 of 24 cases (25%), BRAF mutation in 1 of 13 cases (7.6%), and ret rearrangement in 5 of 12 cases (41.7%). In CPTCs, we found ras mutation in no case, BRAF mutation in 3 of 10 cases (30%), and ret rearrangement in 5 of 11 cases (45%). One FVPTC exhibited simultaneous ras mutation and ret/PTC1 rearrangement, and one CPTC harbored simultaneous BRAF mutation and ret/PTC3 rearrangement. Based on these findings, we concluded that ras mutation correlates with follicular differentiation of thyroid tumors whereas ret activation is associated with papillary nuclei but not with papillary architecture. ret activation is not exclusive of ras or BRAF mutation, whereas ras and BRAF mutations are mutually exclusive. The implications of these results for follicular and papillary carcinogenesis are discussed.     

BRAF T1799A mutation occurring in a case of malignant struma ovarii

Struma ovarii is an extremely rare tumor that occasionally undergoes malignant transformation. Because struma ovarii is composed of thyroid tissue, it is conceivable that the pathogenetic events involved in thyroid follicular transformation may take place also in struma ovarii. The authors describe a case of a classical variant of papillary thyroid carcinoma arising in a struma ovarii of a 22-year-old female. The tumor was heterozygous for BRAF T1799A mutation. No ret/ PTC-1 or ret/PTC-3 rearrangements were detected. This finding would suggest that malignant struma ovarii is similar histologically and genetically to primary papillary thyroid carcinoma.     

Mutations of the BRAF gene in papillary thyroid carcinoma and in Hashimoto's thyroiditis

The purpose of the present study was to investigate the frequency of BRAF mutations in human papillary thyroid carcinoma (PTC) and Hashimoto's thyroiditis (HT) and to evaluate the association of the BRAF mutation with the clinicopathological features of both of these thyroid disorders. A total of 51 PTC with no HT, 28 PTC with HT and 27 HT with no PTC were evaluated using DNA extracted from paraffin-embedded specimens. BRAF mutations were analyzed by direct DNA sequencing of the polymerase chain reaction (PCR)-amplified exon 15. The BRAF missense mutation at codon 599 (T1796A) was present in 46 of 51 PTC (90%) with no HT, 18 of 28 PTC (64%) with HT, four of 28 HT (14%) with PTC, and zero of 27 HT with no PTC. The BRAF mutation at codon 600 (A1798G) was not detected in any case. Clinicopathological examination of 106 patients with either PTC or HT showed that the BRAF mutation was significantly correlated with patient age. These data indicate that the BRAF mutation is associated with a valuable biological property of PTC and may participate in the pathogenesis of PTC arising in HT. These results indicate that the detection of the BRAF mutation in HT can be helpful for prediction of progress to PTC.     

Mutations of the BRAF gene in papillary thyroid carcinoma in a Korean population

The B-type Raf kinase (BRAF) protein is a serine/threonine kinase that has an important role in cellular proliferation, differentiation, and programmed cell death. The BRAF gene has been recently found to be mutated in human carcinomas, predominantly in malignant melanoma. The aim of this study was to investigate the frequency of the BRAF mutation in papillary thyroid carcinoma (PTC) of Koreans through direct DNA sequencing of the polymerase chain reaction (PCR)- amplified exon 15 with clinicopathological features. Seventy paraffin-embedded conventional papillary carcinomas in the thyroid gland were evaluated. The BRAF missense mutation at V599E was found in 58 of 70 PTCs (83%). The frequency of our series was much higher than the frequencies of other PTC series (36 - 69%). The frequency of nodal metastasis was also significantly higher in the BRAF mutation group (p= 0.048). These results suggest that the BRAF mutation is involved in the carcinogenesis in most conventional PTCs, especially those occurring in Koreans, and this is a potentially valuable marker for the evaluation of prognosis of patients with PTC. These findings support the specific inhibitors of BRAF being promising targets for the disease outcome.     

Diffuse sclerosing variant of papillary thyroid carcinoma: lack of BRAF mutation but occurrence of RET/PTC rearrangements.

Diffuse sclerosing variant of papillary thyroid carcinoma (PTC) is a rare tumour with a characteristic morphology as well as a strong preponderance for younger female patients. The T1799A missense mutation in exon 15 of the BRAF gene and RET/PTC rearrangement have been identified as the dominant genetic tumour initiation events in the pathogenesis of PTC leading to a constitutive activation of the RAS-RAF-MAPK pathway. In order to elucidate the pathogenesis of diffuse sclerosing variant of PTC, the prevalence of BRAF mutation and RET/PTC were determined by RT-polymerase chain reaction and DNA-sequence analysis in tumour samples of seven patients with this variant (all female, age range 15-61 years, mean 33.3 years) without prior radiation exposure. None of these cases showed a BRAF mutation. RET/PTC1 (two out of seven) and RET/PTC3 (one out of seven), which have been shown in large PTC series to comprise together more than 90% of RET/PTC types, were found in <50% of the cases investigated. All seven samples expressed the RET tyrosine kinase domain but lacked its extracellular domain potentially suggesting the existence of rare types of RET/PTC rearrangement in the four remained cases of diffuse sclerosing variant of PTC. Regarding this subtype, our study confirmed the paradigm of a mutual exclusivity between RET/PTC and BRAF in PTC. Additionally, this rare variant of papillary thyroid carcinoma may represent a tumour type susceptible to RET-targeted therapies.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.     

甲状腺乳头状癌BRAF基因突变的检测及临床意义

目的 了解甲状腺乳头状癌(papillary thyroid carcinoma,PTC)BRAF基因T1799A点突变的情况与临床病理学特征的关系.方法 应用聚合酶链反应及DNA直接测序法对43例PTC患者,20例非PTC甲状腺病变患者及40份正常甲状腺组织对照的新鲜标本进行BRAF基因检测.分析BRAF基因突变与性别、发病年龄、原发灶大小、甲状腺包膜外浸润、颈淋巴结转移及远处转移等临床病理学特征的关系.结果 43例PTC中1 7例检出BRAF基因T1799A点突变.检出率为39.5%,而在非PTC甲状腺病变患者和40份正常甲状腺组织未发现T1799A点突变.BRAF基因突变与PTC甲状腺包膜外浸润及颈淋巴结转移密切相关(P<0.05及P<0.05),与性别、发病年龄、原发灶大小及远处转移无关.结论 BRAF基因突变与颈淋巴结转移和甲状腺包膜外浸润密切相关,突变可能增加PTC的侵袭性并影响预后.