Proteome analysis identified maspin as a special feature of papillary thyroid carcinoma

This study aimed at investigating new mechanisms of carcinogenesis in thyroid cancer at the molecular level and at finding potential protein markers involved in the initiation of the different histological subtypes. For this, we performed differential proteome analysis on primary cultured thyrocytes (PT) and transformed thyrocytes (TT) derived from 238Pu alpha-particle irradiation using 2-dimensional electrophoresis (2-DE) and peptide mass fingerprinting (PMF) with matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS). Image analysis showed that one protein was very strongly expressed in TT; 55 proteins were weaker, different in intensity, including 26 spots that were increased in PT, and 29 spots were decreased. The hot spot was identified as maspin, a unique member of the serpin family considered to be a class II tumor suppressor gene. To clarify the role of maspin in thyroid carcinogenesis we searched for protein expression in 20 normal (tumor-free) tissues, as well as in 20 follicular adenomas (FAD), 20 papillary carcinomas (PTC), 20 follicular carcinomas (FTC), 20 poorly differentiated carcinomas (PDTC), and 20 undifferentiated carcinomas (UTC). Maspin protein expression was detectable in none of the cases of normal tumor-free thyroid tissue, nor in FAD, FTC, PDTC and UTC. In contrast 14 of 20 PTC (70%) showed a moderate or strong cytoplasmic staining; 4 of these 14 cases had a moderate cytoplasmic and nuclear staining. In conclusion, we hypothesize that maspin protein expression is a special feature in the cascade of PTC genesis and that the way of initiating PTC is different from other thyroid carcinoma types.     

Expression of telomerase genes in thyroid carcinoma

Telomerase (T) is a ribonucleoprotein complex that includes the telomerase RNA component (hTR), telomerase associated protein (TP1) and the telomerase catalytic subunit (hTERT). Telomerase has been shown in stem cells and found to be activated in tumor tissues and immortalized cells. We wanted to test whether the expression of the telomerase complex subunits correlate with the enzyme activity in human thyroid tissue. Hence, we determined the expression of hTERT, hTR and TP1 mRNA by RT-PCR and compared the results to telomerase activity as detected by the telomeric repeat amplification protocol (TRAP) assay. Fifteen benign goiters (G), 11 follicular carcinomas (FTC) including 2 oncocytic follicular carcinomas (also called Hurthle cell carcinoma, oFTC), 12 papillary carcinomas (PTC) including 3 microcarcinomas (mPTC), and 12 undifferentiated anaplastic thyroid carcinomas (UTC) were investigated. Experienced pathologists performed histological and pTNM classification in each specimen. RT-PCR analysis revealed that TP1 was ubiquitously expressed in all G and carcinomas. hTR was expressed in 4 out of 15 G, in 2 out of 3 mPTC, in 5 out of 9 PTC, in 5 out of 9 FTC, in all oFTC and in 9 out of 12 UTC samples. Regarding all carcinomas, no statistically significant correlation was observed between hTR-expression and tumor stage, lymph node or distant metastasis. hTERT-expression was associated with malignancy and tumor stage. All mPTC and 13 out of 15 G did not express hTERT, whereas all samples of pT3-4 tumor stage of FTC, PTC, UTC and all oFTC were positive for hTERT. No telomerase activity could be detected in G. Telomerase activity in carcinoma was only measurable in tissues that expressed the catalytic subunit hTERT. Our data indicate that telomerase activity is up-regulated in neoplastic cells. In contrast to TP1 and hTR, hTERT and telomerase activity may be of help in identifying invasive tumors and may be additional markers for classification of benign goiter and malignant thyroid carcinoma.     

The Role of Claudin-1 Expression in Follicular and Papillary Thyroid Neoplasm

Objective: This study evaluated differences in Claudin-1 expression between follicular adenoma (FA), follicular thyroid carcinoma (FTC), follicular variant papillary thyroid carcinoma (FV-PTC), and papillary thyroid carcinoma (PTC). Material and methods: This study used a cross-sectional approach. Immunostaining using the polyclonal antibody Claudin-1 was performed on 75 samples divided into 20 samples for follicular adenoma, follicular thyroid carcinoma, papillary carcinoma, and 15 samples of follicular variant thyroid carcinoma, respectively. Results: Claudin-1 expression is detected on the cytoplasmic membrane of tumor cells and appears to be varied among thyroid neoplasms. The claudin-1 expression score revealed a statistically significant difference between FA against FV-PTC, FA versus (vs) PTC, and FTC vs PTC, with median values of 4 vs 6 (p = 0.016), 4 vs 8 (p = 0.001), and 5 vs 8 (p = 0.002), respectively. However, there was no statistically significant difference in scores between the FA and the FTC (4 vs 5), or between the FTC and the FV-PTC groups (5 vs 6 (p=1,000). Conclusion: These results suggest that Claudin-1 may be capable of discriminating follicular adenoma from classic and follicular variant of papillary thyroid carcinoma. It can also differentiate follicular thyroid carcinoma and papillary thyroid carcinoma, especially for cases challenging to assess by hematoxylin and eosin staining. It still holds promise in providing targeted cancer therapy.     

细胞角蛋白-19 波形蛋白血管内皮生长因子-C和环氧化物酶-2 在甲状腺乳头状癌和滤泡癌中的表达及意义

目的:探讨细胞角蛋白-19（CK- 19）、波形蛋白（Vimentin）、血管内皮生长因子-C（VEGF-C）和环氧化物酶-2（COX-2）表达与甲状腺乳头状癌和滤泡癌分化、浸润、转移的关系。方法:采用免疫组织化学SP法检测94例乳头状癌和54例滤泡癌中CK- 19、Vimentin、VEGF-C、COX-2 的表达。结果:CK- 19、VEGF-C、COX-2 表达于癌细胞的胞浆,Vimentin 在癌组织的间质和癌细胞的胞浆均有表达,其表达差异从阳性率和阳性强度两个方面予以统计分析。乳头状癌中CK- 19表达的阳性率（90.4%）高于滤泡癌（61.1%）,Vimentin、VEGF-C 和COX-2 表达的阳性率（100% 、86.2% 、81.9%）近似于滤泡癌（100% 、87.0% 、81.5%）。 乳头状癌无转移组和有转移组（含原发灶和转移灶）四种指标的阳性率均相近,滤泡癌高分化型组与低分化型组相比,除Vimentin 的阳性率均为100% 外,其他三种指标CK- 19、VEGF-C、COX-2 均为高分化型组阳性率（74.1% 、88.9% 和85.2%）,高于低分化型组阳性率（48.1%、85.2%和77.8%）。 Vimentin 和VEGF-C 的免疫阳性表达强度在乳头状癌中高于滤泡癌,CK- 19和COX-2 在乳头状癌和滤泡癌中的表达相近。四种免疫学指标的免疫阳性强度在乳头状癌原发灶、转移灶、滤泡癌高分化组、低分化型组间均无明显差异。乳头状癌中CK- 19与Vimentin 间免疫表达强度无相关性,VEGF-C 和COX-2 间呈正相关关系。结论:综合检测CK- 19、Vimentin、VEGF-C 和COX-2 四种免疫学指标,对探讨甲状腺乳头状癌和滤泡癌分化、浸润、转移和预后评估具有一定的参考价值。      

环氧化酶-2在分化型甲状腺癌中的表达及意义

目的探讨环氧化酶-2（COX-2）在甲状腺乳头状癌与滤泡癌中的表达及其临床意义。方法采用免疫组织化学SP法,检测36例甲状腺乳头状癌和15例甲状腺滤泡癌中COX-2的表达。结果 COX-2表达于癌细胞的胞质,其阳性表达率乳头状癌组（72.22%）高于滤泡癌组（40.00%）,有淋巴结转移组（78.57%）高于无淋巴结转移组（43.48%）,差异均有统计学意义,COX-2表达还与肿瘤TNM分期有关。结论 COX-2对分化型甲状腺癌的转移起重要作用,其具体机制还有待进一步研究。     

High Expression of Claudin-1 Protein in Papillary Thyroid Tumor and its Regional Lymph Node Metastasis

Claudins, known as major contributors in the formation of the tight junction, are differentially expressed in malignant tumors as compared to the corresponding healthy tissues. Therefore, they are thought to play a role in carcinogenesis and tumor progression. Altered expression of claudin-1 has been reported in several tumor types including endometrial, papillary renal cell and colonic carcinoma, and increased claudin-1 mRNA levels have been observed in papillary thyroid carcinoma (PTC). In this study, we aimed at determining the pattern of claudin-1 expression in various types of thyroid lesions at the protein level and investigating the immunolocalization of β-catenin reported to regulate claudin-1 expression. Samples included 19 PTCs, ten cases of corresponding regional lymph node metastasis, eight papillary microcarcinomas (PMC), 17 follicular thyroid carcinomas (FTC) and 19 follicular adenomas (FA). All cases were evaluated by quantitative immunohistochemistry. Conspicuous claudin-1 immunostaining was detected in the majority of PTC/PMC primary tumors and lymph node metastases (19/27 and 9/10, respectively). On the other hand, we found weak or no claudin-1 expression in any of the FA and FTC cases or peritumoral non-malignant thyroid tissues. Our data prove that high claudin-1 protein expression is specific for PTC and its regional lymph node metastases, while we failed to verify that claudin-1 is regulated by β-catenin in thyroid tumors. Based on these results, claudin-1 may be a useful tumor marker for PTC.     

P53 gene alterations in differentiated thyroid cancers

Analysis of 22 human thyroid cancers including papillary, follicular and medullary subtypes (PTC, FTC, MTC) by PCR-SSCP, and immunohistochemistry detected 4 deletions and 3 mutations. Deletions involved exons 1, 2-3 and 5-6 in 3 PTCs, mutations exons 2-3 in 2 MTCs and exons 8-9 in PTC4. p53 alterations occurred in 2/5 recurrent tumors and 2/3 tumors developing to cell lines. Immuno-histochemistry detected p53 mutations in differentiated areas of papillary thyroid cancers as frequent events occurring at stage T1 to T4 in contrast to prior findings by other authors which restrict p53 alterations to undifferentiated stages.     

Expression of pendrin in benign and malignant human thyroid tissues

The Pendred syndrome gene (PDS) encodes a transmembrane protein, pendrin, which is expressed in follicular thyroid cells and participates in the apical iodide transport. Pendrin expression has been studied in various thyroid neoplasms by means of immunohistochemistry (IHC), Western blot and RT-quantitative real-time PCR. The expression was related to the functional activity of the thyroid tissue. Follicular cells of normal, nodular goitre and Graves' disease tissues express pendrin at the apical pole of the thyrocytes. In follicular adenomas, pendrin was detected in cell membranes and cytoplasm simultaneously in 10 out of 15 cases. Pendrin protein was detected in 73.3 and 76.7% of the follicular (FTC) and papillary (PTC) thyroid carcinomas, respectively, where pendrin was solely localised inside the cytoplasm. An extensive intracellular immunostaining of pendrin was observed in six out of 11 (54.5%) of positive FTCs and 19 out of 23 (82%) of PTCs. Focal reactivity was detected in one follicular- and three papillary carcinomas, whereas pendrin protein was absent in three of 15 FTC and four of 30 PTC; mRNA of pendrin was detected in 92.4% of thyroid tumours. The relative mRNA expression of pendrin was lower in cancers than in normal thyroid tissues (P<0.001). The pendrin protein level was found to parallel its mRNA expression, which was not, however, related to the tumour size and tumour stage. In conclusion, pendrin is expressed in the majority of differentiated thyroid tumours with high individual variability but its targeting to the apical cell membrane is affected.     

山东省沿海与内陆甲状腺癌患病模式变迁

目的：观察沿海城市（青岛市）和内陆城市（临沂市）11年来甲状腺乳头状癌（PTC）、滤泡型癌（FTC）、髓样癌（MTC）、未分化癌（ATC）患病率的变化趋势,并将内陆城市与沿海城市进行比较,以探讨碘营养与甲状腺癌的关系。方法：根据国际肿瘤分类标准,利用石蜡切片等方法对青岛大学医学院附属医院病理科、临沂市人民医院病理科和临沂市第二人民医院病理科1998年-2008年间收检的甲状腺恶性肿瘤进行重新分类,回顾性分析患者的平均确诊年龄、性别比例、构成比。结果：11年来4类甲状腺恶性肿瘤沿海城市（青岛）的总例数为734例,其中PTC占85.56%、FTC占8.86%、MTC占4.36%、ATC占1.22%。4类中女性发病均高于男性（男女比例1∶1.25-3.94）。PTC的平均确诊年龄最低（45.39岁）,ATC最高（61.56岁）。内陆城市（临沂）的总例数为421例,其中PTC占82.90%、FTC占9.74%、MTC占4.75%、ATC占2.61%。4类甲状腺癌中女性发病均高于男性（男女比例1∶2.33-7.20）。PTC的平均确诊年龄最低（42.09岁）,ATC最高（67.91岁）。沿海与内陆的PTC均呈逐年递增趋势,FTC、MTC和ATC递增趋势不明显。结论：11年来沿海与内陆的PTC均呈逐年递增趋势,FTC、MTC和ATC递增趋势不明显。内陆PTC患病年龄低于沿海。碘营养等因素可能参与PTC的发生,其确切机制值得进一步研究。     

P21WAF1/CLP1在甲状腺癌组织的表达及临床意义

[目的]探讨p21WAF/CLP与p53基因在甲状腺癌中的表达与病理类型和分化程度的关系。[方法］应用免疫组化技术检测甲状腺癌组织中的抑癌基因p2lWAF/CLPl及p53基因的表达。统计学采用x2检验。[结果]甲状腺腺瘤(TT),甲状腺乳头状癌(PTC)、滤泡状癌(FTC)、未分化癌(UDC)组织p21蛋白阳性率分别为66.7％、62 5％、58.3％、50.0％,各组之间无显著差别(P＞0.05);高分化癌(WDC)、低分化癌(PDC)、UDC组织p21蛋白阳性率分别为67.7％、46.2％、50.0％,各组之间无显著差别(P＞0.05);PTC、FTC、UDC组织p53蛋白阳性率分别为31.3％、25.0％、64.3％,UDC与PTC、FTC之间存在显著差别(P＜0 05);WDC、PDC、UDC组织p53蛋白阳性率分别为l6.1％、61.5％、64.3％,WDC的阳性率明显低于PDC、UDC(P＜0.05);p53蛋白阳性的癌组织p21蛋白阳性率为40.9％(9/22),p53蛋白阴性的癌组织p21蛋白阳性率为69.4％(25/36),两者之间存在显者差异(P＜0 05)。[结论］甲状腺癌中p21WAF/CLP的表达与其病理类型和分化程度无关,而p53基因的表达与甲状腺癌病理类型和分化程度有关,p2WAFl/CLPl作为一新的抑癌基因,其表达相当程度上依赖于p53蛋白。     

Genetic alterations and their relationship in the phosphatidylinositol 3-kinase/Akt pathway in thyroid cancer.

PURPOSE: To investigate the overall occurrence and relationship of genetic alterations in the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in thyroid tumors and explore the scope of this pathway as a therapeutic target for thyroid cancer. EXPERIMENTAL DESIGN: We examined collectively the major genetic alterations and their relationship in this pathway, including PIK3CA copy number gain and mutation, Ras mutation, and PTEN mutation, in a large series of primary thyroid tumors. RESULTS: Occurrence of any of these genetic alterations was found in 25 of 81 (31%) benign thyroid adenoma (BTA), 47 of 86 (55%) follicular thyroid cancer (FTC), 21 of 86 (24%) papillary thyroid cancer (PTC), and 29 of 50 (58%) anaplastic thyroid cancer (ATC), with FTC and ATC most frequently harboring these genetic alterations. PIK3CA copy gain was associated with increased PIK3CA protein expression. A mutual exclusivity among these genetic alterations was seen in BTA, FTC, and PTC, suggesting an independent role of each of them through the PI3K/Akt pathway in the tumorigenesis of the differentiated thyroid tumors. However, coexistence of these genetic alterations was increasingly seen with progression from differentiated tumor to undifferentiated ATC. Their coexistence with BRAF mutation was also frequent in PTC and ATC. CONCLUSIONS: The data provide strong genetic implication that aberrant activation of PI3K/Akt pathway plays an extensive role in thyroid tumorigenesis, particularly in FTC and ATC, and promotes progression of BTA to FTC and to ATC as the genetic alterations of this pathway accumulate. Progression of PTC to ATC may be facilitated by coexistence of PI3K/Akt pathway-related genetic alterations and BRAF mutation. The PI3K/Akt pathway may thus be a major therapeutic target in thyroid cancers.     

Notch-1信号通路在甲状腺癌中作用的研究进展

Notch信号通路参与调控机体细胞的增殖、分化、凋亡等，人类Notch信号通路包括了四种受体及五种配体，其中Notch-1受体在甲状腺癌中发挥重要作用。然而，Notch-1在甲状腺乳头状癌中的作用仍存在争议，大多数学者认为Notch-1信号通路能够促进乳头状癌细胞增殖、侵袭转移，且其表达水平与甲状腺乳头状癌侵袭性相关。而对于甲状腺滤泡状癌、髓样癌及未分化癌细胞，活化Notch-1信号通路可抑制他们的增殖。众多研究表明Notch-1信号通路有望成为甲状腺癌重要治疗靶点。本文就Notch-1在甲状腺癌发生、发展中的作用进行综述。     

GABA Receptor Expression in Benign and Malignant Thyroid Tumors

Neurotransmitter systems have recently been shown to be involved in multiple malignancies including breast, colon and prostate cancers. The role of neurotransmitters and neurotrophic factors has not yet been examined in thyroid cancer. To determine the possible involvement of neurotransmitter systems in thyroid carcinogenesis we characterized the patterns of gamma-aminobutyric acid (GABA) receptor expression in normal thyroid and thyroid tumors. We examined the expression patterns of the GABAergic system in 70 human thyroid tumor samples (13 follicular adenomas, 14 follicular carcinomas, 43 papillary carcinomas) and adjacent normal thyroid by immunohistochemistry. GABAergic system mRNA expression in thyroid cancer cell lines derived from primary (FTC133) and metastatic tumors (FTC236 and FTC238) was examined by real time PCR. Overall, GABA receptor expression is increased in tumors compared to normal thyroid tissue. Expression of GABAA receptor β2 was detected in the vasculature of normal thyroid and thyroid tumors but not in thyroid cancer cells. GABAA α2 was detected in metastatic-derived but not in primary-tumor derived cell lines. Expression levels of GABAB R2 and GABA receptor associated protein (GABARAP) are increased in adenomas and thyroid cancer suggesting their role in early stages of thyroid tumorigenesis. This study represents the first demonstration of GABA receptor expression in human thyroid tissue and suggests that the GABAergic system is involved in thyroid carcinogenesis.     

NIS蛋白在良恶性甲状腺疾病中的表达

目的:通过免疫组织化学方法,观察组织中碘钠同向转运体（sodium/iodide symporter,NIS）蛋白在甲状腺疾病中的表达情况,并探讨其临床应用价值。方法:选取我院病理科存档的甲状腺外科56例手术患者的蜡块标本,其中甲状腺癌40例,包括滤泡状腺癌2例、乳头状癌38例;未分化癌2例;甲状腺良性病变14例(甲状腺腺瘤7例,原发性甲状腺功能亢进7例)。应用免疫组织化学法处理,观测NIS的表达情况。结果:分化型甲状腺癌、未分化癌、甲状腺腺瘤、原发性甲状腺功能亢进中NIS蛋白阳性率分别为90.00%、50.00%、42.86%、100.00%,在癌旁组织中表达阳性率为66.67%。NIS在原发性甲亢患者组织的细胞膜上表达水平显著高于其他分型,各组对比有显著差异（P＜0.01）。结论:NIS功能蛋白定位于细胞膜,在不同甲状腺疾病组织中的表达水平有所差异;在不同甲状腺疾病中,NIS分布有明显差异,行131I放射治疗时,可以考虑其NIS分布情况,给予个体化调整。