超声引导下细针穿刺研究ret基因活化与人类甲状腺癌的关系

目的研究ret基因的活化与人类甲状腺癌的关系.方法对50例高度怀疑甲状腺癌的甲状腺结节患者采用超声引导下细针穿刺技术与RT-PCR技术相结合,研究活检组织中ret基因的活化形式PTC基因的表达.结果乳头状癌26例,其中有7例(27%)PTC基因表达阳性;另24例中滤泡状癌10例,未分化癌2例,腺瘤5例,结节性甲状腺肿7例,均未见PTC基因表达.结论 ret基因的活化仅出现在甲状腺乳头状癌中,因此对PTC基因的检测可作为人类乳头状癌的鉴别诊断和判断生物学行为的有效指标.     

Oncogenes and thyroid cancer.

Human thyroid tumors can be derived either from epithelial follicular cells or from parafollicular C-cells. Follicular cell-derived tumors represent a wide spectrum of lesions, ranging from benign adenomas through differentiated (follicular and papillary) and undifferentiated (anaplastic) carcinomas, thus providing a good model for finding a correlation between specific genetic lesions and histologic phenotype. Follicular adenomas and carcinomas show frequently the presence of mutations in one of the three ras genes. Papillary carcinomas show frequently a specific gene rearrangement which gives rise to the formation of several types of so-called RET/PTC chimeric genes. This lesions occur in almost 50% of papillary cancers and consist in the juxtaposition of the 3' or tyrosine kinase domain of the RET gene (which codes for a receptor protein not normally expressed in follicular thyroid cells) with the 5' domain of ubiquitously expressed genes, which provide the promoter and dimerization functions, necessary for the constitutive activation of RET/PTC proteins. Anaplastic carcinomas are frequently associated with mutations of the p53 tumor suppressor. Finally, point mutations of the RET gene are found in familial endocrine syndromes (FMTC; MEN2A and MEN2B), a common feature of which is the medullary thyroid carcinoma, a malignant tumor derived from parafollicular C-cells.     

High prevalence of mutations of the p53 gene in poorly differentiated human thyroid carcinomas.

The development and progression of thyroid tumors is signaled by phenotype-specific mutations of genes involved in growth control. Molecular events associated with undifferentiated thyroid cancer are not known. We examined normal, benign, and malignant thyroid tissue for structural abnormalities of the p53 tumor suppressor gene. Mutations were detected by single-strand conformation polymorphisms of PCR-amplified DNA, using primers bracketing the known hot spots on either exons 5, 6, 7, or 8. The prevalence of mutations was as follows: normal thyroid 0/6; follicular adenomas 0/31; papillary carcinomas 0/37; medullary carcinomas 0/2; follicular carcinomas 1/11; anaplastic carcinomas 5/6; thyroid carcinoma cell lines 3/4. Positive cases were confirmed by direct sequencing of the PCR products. All five anaplastic carcinoma tissues and the anaplastic carcinoma cell line ARO had G:C to A:T transitions leading to an Arg to His substitution at codon 273. In both tumors and cell lines, examples of heterozygous and homozygous p53 mutations were identified. The only thyroid carcinoma cell line in which p53 mutations were not detected in exons 5-8 had markedly decreased p53 mRNA levels, suggesting the presence of a structural abnormality of either p53 itself or of some factor controlling its expression. The presence of p53 mutations almost exclusively in poorly differentiated thyroid tumors and thyroid cancer cell lines suggests that inactivation of p53 may confer these neoplasms with aggressive properties, and further loss of differentiated function.     

Medullary thyroid carcinoma and other rare types of thyroid carcinoma

Among 4 major traditional groups of thyroid carcinoma, papillary and follicular carcinomas are most common, and other forms, anaplastic and medullary carcinomas, are relatively rare. The 2003 WHO histological classification of thyroid tumor separated 7 other malignant thyroid tumors into distinct pathological entities, such as poorly differentiated, squamous cell, mucinous carcinomas, carcinoma showing thymus-like differentiation (CASTLE), etc. Although they are also extremely rare, recognition of their clinicopathologic features are very important. In this review, not only diagnostic and therapeutic strategies for the rare forms of thyroid carcinomas, specifically focussed on medullary carcinoma and CASTLE, but also their histogenetic abnormalities were discussed.     

Gene abnormalities in thyroid cancer

A number of genetic abnormalities in oncogenes or anti-oncogenes have been identified in association with thyroid carcinogenesis. Especially, oncogenes such as ras mutation, ret/PTC and Braf mutation that constitutively activate MAP kinase pathway a refrequently found in papillary thyroid cancer. The p53 mutation aggravates differentiated thyroid cancers to anaplastic thyroid cancer. These gene alterations are studied not only to understand basically the mechanisms of oncogenesis but also to develop clinically genetic diagnosis or molecular target therapy. In this article, we review the genetic diagnostic methods and phenotype-genotype relationship of human thyroid cancers.     

EpCAM overexpression in thyroid carcinomas: a histopathological study of 121 cases

Epithelial cell adhesion molecule (EpCAM) is expressed by a broad variety of carcinoma cells. It is recognized by the monoclonal antibody 17-1A, which has already been applied for immunotherapy of several carcinoma types in preclinical and small clinical studies. In the present study the immunohistochemical properties of 17-1A were evaluated in 121 cases of thyroid carcinomas of follicular cell origin, comprising of 75 differentiated (DTC; 35 papillary and 40 follicular carcinomas), 24 poorly differentiated (PDTC) and 22 anaplastic thyroid carcinomas. Overexpression of EpCAM, as recently defined, was found with a distinct membranous staining pattern in 81.3% of DTCs and in 66.6% of PDTCs. In contrast, all anaplastic thyroid carcinomas (0%) completely lacked EpCAM expression. Normal thyroid tissue presented with weak and heterogeneous EpCAM staining. This study demonstrates EpCAM overexpression as a common finding in DTCs and PDTCs, and thus these tumors as possible novel targets for EpCAM-directed immunotherapy. Our findings suggest that patients with recurrent or advanced tumor disease and metastatic spread could benefit from this modern therapeutic regime, especially after insufficient radioiodine therapy.     

Clonal composition of benign and malignant human thyroid tumors.

We determined clonality of thyroid tumors from female patients who had restriction fragment length polymorphisms (RFLP) in the X chromosome genes hypoxanthine phosphoribosyltransferase (HPRT) or phosphoglycerate kinase (PGK). We screened normal thyroid tissue from 59 female patients; of the informative cases 14 were heterozygous for a Bgl I site on PGK and 4 were heterozygous for a Bam HI site on HPRT. In monoclonal tumors, one of the polymorphic alleles was selectively digested after additional digestion with Hpa II, a methylation sensitive enzyme, whereas in polyclonal tissue both were decreased to a similar extent. Normal thyroid tissue from all patients showed a polyclonal pattern. Of the 18 tumors studied, 12 were solitary thyroid nodules, and 6 were obtained from multinodular goiters (MNG). The following were monoclonal: 6/6 follicular adenomas, 2/2 follicular carcinomas, and 1/1 anaplastic carcinoma. Two of the three papillary carcinomas showed intermediate patterns, possibly due to contaminating effects of stromal tissue present in most of these neoplasms. Of the six nodules from MNG, four were polyclonal. The two largest gave a distinct monoclonal pattern. Most solitary thyroid tumors are monoclonal, supporting a somatic cell mutation model of thyroid neoplasm formation. Nodules from MNG are largely hyperplastic, although monoclonal neoplasms do occasionally arise within these glands. The specific somatic mutations leading to clonal expansion and determination of tumor phenotype are presently unknown.     

Targeting BRAFV600E in thyroid carcinoma: therapeutic implications

B-Raf is an important mediator of cell proliferation and survival signals transduced via the Ras-Raf-MEK-ERK cascade. BRAF mutations have been detected in several tumors, including papillary thyroid carcinoma, but the precise role of B-Raf as a therapeutic target for thyroid carcinoma is still under investigation. We analyzed a panel of 93 specimens and 14 thyroid carcinoma cell lines for the presence of BRAF mutations and activation of the mitogen-activated protein/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. We also compared the effect of a B-Raf small inhibitory RNA construct and the B-Raf kinase inhibitor AAL881 on both B-Raf wild-type and mutant thyroid carcinoma cell lines. We found a high prevalence of the T1799A (V600E) mutation in papillary and anaplastic carcinoma specimens and cell lines. There was no difference in patient age, B-Raf expression, Ki67 immunostaining, or clinical stage at presentation between wild-type and BRAF(V600E) specimens. Immunodetection of phosphorylated and total forms of MEK and ERK revealed no difference in their phosphorylation between wild-type and BRAF(V600E) patient specimens or cell lines. Furthermore, a small inhibitory RNA construct targeting the expression of both wild-type B-Raf and B-Raf(V600E) induced a comparable reduction of viability in both wild-type and BRAF(V600E) mutant cancer cells. Interestingly, AAL881 inhibited MEK and ERK phosphorylation and induced apoptosis preferentially in BRAF(V600E)-harboring cells than wild-type ones, possibly because of better inhibitory activity against B-Raf(V600E). We conclude that B-Raf is important for the pathophysiology of thyroid carcinomas irrespective of mutational status. Small molecule inhibitors that selectively target B-Raf(V600E) may provide clinical benefit for patients with thyroid cancer.     

Management of differentiated thyroid cancer of the follicular epithelium

Abstract The incidence of thyroid cancer has been increasing in many countries over the last 30 years (from 3.6/100,000 people in 1973 to 8.7/100,000 people in 2002) while mortality has been slowly decreasing ( 1 , 2 ). The increase is mainly represented by papillary thyroid cancer, while follicular and anaplastic histotypes remained stable. It is a general opinion that the increase is attributable to better detection of small papillary carcinomas as a result of improved diagnostic accuracy (neck ultrasound and fine-needle aspiration cytology). Consequently, it is common experience in thyroid cancer referral centers that nearly 60%-80% of thyroid carcinomas detected nowadays are micropapillary thyroid carcinomas (less than 1 cm in size) carrying an excellent long-term prognosis. In view of this change in the presentation of the disease, the objective of thyroid cancer management should be aimed at achieving complete cure using the less aggressive diagnostic and therapeutic procedures.     

Management of differentiated thyroid cancer of the follicular epithelium

Abstract

The incidence of thyroid cancer has been increasing in many countries over the last 30 years (from 3.6/100,000 people in 1973 to 8.7/100,000 people in 2002) while mortality has been slowly decreasing (). The increase is mainly represented by papillary thyroid cancer, while follicular and anaplastic histotypes remained stable. It is a general opinion that the increase is attributable to better detection of small papillary carcinomas as a result of improved diagnostic accuracy (neck ultrasound and fine-needle aspiration cytology). Consequently, it is common experience in thyroid cancer referral centers that nearly 60%–80% of thyroid carcinomas detected nowadays are micropapillary thyroid carcinomas (less than 1 cm in size) carrying an excellent long-term prognosis. In view of this change in the presentation of the disease, the objective of thyroid cancer management should be aimed at achieving complete cure using the less aggressive diagnostic and therapeutic procedures.     

Small-molecule MAPK inhibitors restore radioiodine incorporation in mouse thyroid cancers with conditional BRAF activation

Advanced human thyroid cancers, particularly those that are refractory to treatment with radioiodine (RAI), have a high prevalence of BRAF (v-raf murine sarcoma viral oncogene homolog B1) mutations. However, the degree to which these cancers are dependent on BRAF expression is still unclear. To address this question, we generated mice expressing one of the most commonly detected BRAF mutations in human papillary thyroid carcinomas (BRAF(V600E)) in thyroid follicular cells in a doxycycline-inducible (dox-inducible) manner. Upon dox induction of BRAF(V600E), the mice developed highly penetrant and poorly differentiated thyroid tumors. Discontinuation of dox extinguished BRAF(V600E) expression and reestablished thyroid follicular architecture and normal thyroid histology. Switching on BRAF(V600E) rapidly induced hypothyroidism and virtually abolished thyroid-specific gene expression and RAI incorporation, all of which were restored to near basal levels upon discontinuation of dox. Treatment of mice with these cancers with small molecule inhibitors of either MEK or mutant BRAF reduced their proliferative index and partially restored thyroid-specific gene expression. Strikingly, treatment with the MAPK pathway inhibitors rendered the tumor cells susceptible to a therapeutic dose of RAI. Our data show that thyroid tumors carrying BRAF(V600E) mutations are exquisitely dependent on the oncoprotein for viability and that genetic or pharmacological inhibition of its expression or activity is associated with tumor regression and restoration of RAI uptake in vivo in mice. These findings have potentially significant clinical ramifications.     

Integrin-linked kinase is a potential therapeutic target for anaplastic thyroid cancer

We investigated integrin-linked kinase (ILK), a focal adhesion serine-threonine protein kinase, as a new molecular target for treating anaplastic thyroid cancer. ILK mediates cell growth and survival signals and is overexpressed in a number of cancers. Therefore, we hypothesized that inhibition of ILK leads to growth arrest and apoptosis of thyroid cancer cells. According to Western blotting, the level of ILK protein was highly expressed in one papillary (NPA187) and four of five (Hth74, DRO, ARO, KAT4, and K4) anaplastic thyroid cancer cell lines. Immunohistochemical analysis of a human tissue microarray revealed that ILK was highly expressed in anaplastic thyroid cancer but not in normal human thyroid tissue. Treating thyroid cancer cell lines with a new ILK inhibitor, QLT0267, inhibited epidermal growth factor-induced phosphorylation of AKT, inhibited cell growth, and induced apoptosis in the NPA187, DRO, and K4 cell lines. QLT0267 also inhibited the kinase activity of immunoprecipitated ILK in four of five cell lines. Tumor volumes in mice treated with QLT0267 were significantly reduced compared with those in untreated mice. In immunohistochemical studies, QLT0267 suppressed phosphorylated p-AKT and angiogenesis (i.e., reduced mean vascular density) and induced apoptosis in both tumor cells and tumor-associated endothelial cells of the thyroid DRO xenografts. In summary, we found that ILK expression and activity were elevated in human anaplastic thyroid cancer and ILK inhibition led to growth arrest and apoptosis in vitro and in vivo. Our results provide preliminary evidence that ILK is a potential therapeutic target for treating anaplastic thyroid cancer.     

甲状腺髓样癌的CGRP原位杂交检测

目的 ＣＧＲＰ在甲状腺髓样癌表达的意义及病理诊断和鉴别诊断的价值。方法 选择甲状腺髓样癌１０例,乳头状癌５例,滤泡癌５例,未分化癌５例,滤泡型腺瘤５例,行地高辛标记ＣＧＲＰ ｃＤＮＡ探针原位杂交检测。结果 １０例髓样癌和１例滤泡性腺癌呈强阳性;其它均呈阴性。结论 ＣＧＲＰ原位杂交分析是甲状腺髓样癌有价值的诊断和鉴别诊断方法。     

甲状腺肿瘤癌基因产物p21ras表达的免疫组化研究

目的 探讨癌基因产物ｐ２１ｒａｓ表达的意义及在甲状腺肿瘤病理诊断和鉴别诊断中的应用价值。方法 采用免疫组化ＬＳＡＢ法检测了１０例甲状腺腺瘤、１０例不典型腺瘤、２０例乳头状癌、２０例滤泡癌、１０例髓样癌、１０例未分化癌。结果 在甲状腺癌、甲状腺腺瘤和周边正常组织中均有表达,但阳性细胞的量和染色强度有所不同。其分布特点是：癌组织区〉腺瘤区〉正常组织。良恶性肿瘤组间比较Ｐ〈０．０１,差异非常显著。结论 甲状腺癌的发生与ｒａｓ基因的活化和２１ｒａｓ的过量表达关系密切。ｐ２１ｒａｓ的过表达有助于甲状腺良恶性肿瘤的鉴别。     

Gene p53 mutations are restricted to poorly differentiated and undifferentiated carcinomas of the thyroid gland.

The p53 gene was analyzed in tumor specimens obtained from 52 patients with various types of carcinoma of the thyroid gland by a combined molecular and immunocytochemical approach. The histologic types included 37 well-differentiated papillary and follicular carcinomas, 8 poorly differentiated, and 7 undifferentiated carcinomas. The p53 gene was shown to be unaffected in all differentiated tumors by single-strand conformation polymorphism analysis. However, in two out of eight (25%) of poorly differentiated carcinomas and five out of seven (71%) undifferentiated carcinomas, p53 mutations were identified and subsequently characterized by DNA sequencing. One undifferentiated carcinoma displayed two areas with varying degrees of differentiation. The comparative analysis of the p53 gene, in both the more and the less differentiated area of this tumor, clearly showed that the p53 mutation was confined to the latter component of the tumor specimen. These results indicate that mutations of the p53 gene are associated with the most aggressive histologic types of thyroid tumors, such as the undifferentiated carcinoma and, to a certain extent, the poorly differentiated carcinoma, and that the alterations of this gene represent a late genetic event in human thyroid carcinogenesis.     

Characteristics of thyroid carcinomas in aging patients

BACKGROUND: To investigate the clinical features of thyroid cancer in aging patients and to present the results of treatment. From this we can provide bases for earlier diagnoses and better treatment of thyroid malignancies in older patients. MATERIALS AND METHODS: In this study a retrospective analysis was performed with 204 thyroid cancer patients aged 60 years or older (132 women, with a mean age of 68.3 +/- 6.6 years; 72 men, with a mean age of 67.0 +/- 5.3 years). RESULTS: Of the 204 patients, 142 had well-differentiated thyroid carcinomas (96 papillary thyroid carcinomas, 43 follicular carcinomas, three Hürthle cell carcinomas) and three medullary carcinomas. Sixty-nine (33.8%) of the 204 patients died after treatment. Of these, three patients died of causes not related to thyroid cancer. For well-differentiated thyroid carcinomas, male gender, follicular carcinoma, and a larger tumour size indicated a poor prognosis. Of the 59 non-well-differentiated thyroid carcinomas, 39 were anaplastic thyroid carcinomas, nine metastatic cancers of the thyroid, seven lymphomas, and four squamous cell carcinomas. After treatment, 40 (67.8%) of the 59 patients died. In multivariant analysis of the differences in clinical parameters between aging and younger thyroid cancer patients, the current status, tumour size, follow-up period, sex, and stage at diagnosis were independent factors. From this data the delayed diagnosis of aging patients with thyroid cancer was of note when compared with younger patients. CONCLUSION: Thyroid cancer in older patients is not a benign clinical disorder. Early diagnosis and urgent aggressive treatment are recommended courses of action for this type of cancer, especially for non-well-differentiated thyroid cancers.     

A new mechanism of BRAF activation in human thyroid papillary carcinomas

In this issue of the JCI, Ciampi et al. report the identification of a novel oncogene in patients affected by radiation-associated thyroid papillary carcinomas. This oncogene derives from a paracentric inversion of the long arm of chromosome 7, which results in an in-frame fusion of the N-terminus of the A-kinase anchor protein 9 (AKAP9) gene with the C-terminal catalytic domain (exons 9-18) of the serine-threonine kinase BRAF. The resulting AKAP9-BRAF fusion protein shows constitutive kinase activity, and it is able to transmit mitogenic signals to the MAPK pathways and to promote malignant transformation of NIH3T3 cells.     

CD105在不同类型甲状腺癌组织中的表达及与淋巴结转移相关性的研究

目的研究甲状腺癌组织中CD105的表达意义及与淋巴结转移的相关性。方法SP法检测105例存档蜡块标本中CD105的表达。结果正常甲状腺组织、良性甲状腺肿瘤组织标本30例，无CD105的表达。甲状腺乳头状癌标本40例中26例阳性，滤泡状癌20例中17例阳性，未分化癌标本15例中14例阳性，上述两两比较其差异均有显著性；甲状腺乳头状癌中有淋巴结转移的标本24例中22例阳性，无淋巴结转移的标本16例中4例阳性，二者比较其差异均有显著性。结论CD105在正常甲状腺组织、良性甲状腺组织的血管内皮细胞膜上无表达，在甲状腺乳头状癌、滤泡状癌和未分化癌中依次升高。CD105可以作为预测甲状腺癌转移的参考指标。     

Incidental discovery of a Hodgkin lymphoma synchronous to a papillary thyroid carcinoma

Papillary thyroid carcinoma is the most common type of thyroid cancer and accounts for almost 89.4% of all thyroid carcinomas. Hodgkin lymphoma is a heterogeneous group of neoplasms and represents 10% of lymphomas. These two cancers do not share the same risk factors. Some studies have reported the association of thyroid papillary carcinoma with lymphomas, mainly Hodgkin''s lymphoma, treated with radiotherapy. However, to our knowledge less than 10 cases have illustrated synchronous papillary thyroid carcinoma and Hodgkin lymphoma with no history of radiotherapy. We present the case of a 49‐year‐old female patient, with no history of past exposure to radiation, who was incidentally diagnosed with Hodgkin lymphoma during the work up for papillary thyroid carcinoma. Our patient had total thyroïdectomy with cervical lymphadenectomy. The histopathologic examination concluded to a papillary thyroid carcinoma of classical variant. And the lymph node dissection enabled us to diagnose not only papillary thyroid carcinoma''s lymph node metastasis, but also Hodgkin Lymphoma. This discovery of the Hodgkin lymphoma was totally incidental. The discovery of synchronous tumors in patients with papillary thyroid carcinoma has been reported in the literature. However, the diagnosis of Hodgkin through lymph node dissection for papillary thyroid carcinoma is extremely rare. This underlines the singularity and the importance of our case. The synchronous papillary thyroid carcinoma and Hodgkin lymphoma is a rare condition, which may pose significant diagnostic and treatment dilemmas. To date, there is no standardized approach due to lack of experience. The molecular mechanisms of this link are poorly understood and yet remain to be elucidated.     

灰阶及彩色多普勒超声诊断甲状腺恶性肿瘤并颈部静脉瘤栓

目的 评价甲状腺恶性肿瘤合并颈部静脉瘤栓的灰阶及彩色多普勒超声的表现。方法 回顾性分析2010年3月—2014年9月于我院就诊的甲状腺恶性肿瘤合并颈部静脉瘤栓5例患者超声表现及特征。结果 甲状腺乳头状癌2例,低分化甲状腺癌1例,甲状腺未分化癌1例,甲状腺肌源性低度恶性肉瘤1例。超声显示甲状腺肿瘤经甲状腺引流静脉蔓延3例、甲状腺肿瘤直接侵犯颈内静脉1例、转移淋巴结侵犯颈内静脉1例。结论 甲状腺恶性肿瘤并颈部静脉瘤栓灰阶及彩色多普勒超声表现较具特征性,可作为此类疾病的首选检查方法。