甲状腺增殖性疾患组织表皮生长因子及其受体的表达

目的　探讨表皮生长因子 (EGF)及其受体 (EGFR)在甲状腺增殖性疾患中的表达及其作用。方法　应用免疫组化ABC染色方法观察 70例甲状腺组织切片EGF及EGFR的表达。结果(1)EGF在正常、肿瘤及非肿瘤组织中几乎均无表达。 (2 )乳头状、滤泡型甲状腺癌及其混合癌EGFR阳性表达高于非癌疾患及正常组织 (P <0 .0 5 ) ,阳性表达程度以强阳性为主。 (3)在正常组织、良性腺瘤、结节性甲状腺肿及桥本病 ,弱或中度的EGFR阳性表达率各组间差异无显著性。正常组织阳性表达率虽高达 83.3 % ,但 2 / 3表达为弱阳性。 (4 )乳头状甲状腺癌以细胞浆表达EGFR占优势 ,滤泡型及混合型甲状腺癌主要为混合着色 ,但与非癌混合着色不同的是多数以胞浆表达占优势 ;良性疾患以混合染色为主 ,但结节性甲状腺肿以膜着色居多。正常组织为浆、膜混合着色。结论　 (1)对EGFR强阳性表达尤其细胞浆为主者应高度疑及甲状腺癌。 (2 )各甲状腺良性疾患均有不同程度EGFR表达 ,虽无统计学意义上的差别 ,却可说明EGFR对于良性肿瘤及非肿瘤增殖性疾患的生成均有不应忽视的作用。     

Epidermal growth factor receptor and thyrotropin response in human thyroid tissues

The content of epidermal-growth-factor receptor (EGFr) and its relation to TSH-response were examined in 27 malignant thyroid tumors (5 follicular, 6 papillary, 5 medullary, 11 anaplastic carcinomas) and in 30 tumor-like lesions (21 hyperplastic goiters and 9 toxic adenomatous goiters). Normal 12 thyroid tissues adjacent to benign tumors with no evidence of macroscopic or microscopic abnormalities were used as control. All thyroid plasma membranes tested showed specific EGF binding. In membranes from toxic adenomas (2.18 +/- 0.73 fmoles/mg protein) and papillary carcinomas (2.80 +/- 0.80) the EGF binding was similar to that of normal thyroid membranes (2.32 +/- 0.73). Hyperplastic goiters showed an EGF binding (4.4 +/- 0.82) slightly higher than normal tissue. The highest and the lowest EGF binding values were found in anaplastic (11.8 +/- 2.78) and medullary (0.50 +/- 0.39) carcinomas, respectively. An inverse correlation between EGFr content and TSH-response was found when anaplastic thyroid tumors were compared to tumor-like lesions. However no correlation was observed in medullary carcinomas which also failed to respond to TSH and in papillary carcinomas which partially respond to thyrotropin.     

Expression of c-erbB-2 oncoprotein in different types of thyroid tumors: an immunohistochemical study

AIMS: c-erbB-2 expression has been found to be an important prognostic parameter in various types of tumors, but the role played by this oncoprotein in thyroid tumors is still controversial. This study is designed to investigate c-erbB-2 expression in different types of thyroid tumors. METHODS: c-erbB-2 protein over-expression was studied immunohistochemically (IHC) in 68 paraffin-embedded thyroid tumors (12 follicular adenomas, 20 papillary carcinomas, 20 follicular carcinomas, eight medullary carcinomas, eight anaplastic carcinomas), diagnosed at the Pathology Department of Cukurova University. RESULTS: No expression of c-erbB-2 was found in anaplastic carcinomas, but 50% of the papillary carcinomas showed a cytoplasmic staining pattern and 45% had a mixed staining pattern (cytoplasmic and membranous patterns). Eight (40%) of the 20 follicular carcinomas showed a mixed cytoplasmic/membranous staining pattern and three (15%) showed only cytoplasmic reactivity. Cytoplasmic immunoreactivity was detectable for c-erbB-2 in six out of eight (75%) medullary carcinomas. Finally, seven cases of 12 (58%) follicular adenomas showed cytoplasmic staining. CONCLUSIONS: Investigation of the exact role of c-erbB-2 in thyroid tumors requires further studies, and the different patterns of immunostaining may be helpful for determination of prognosis as is the case in breast carcinoma.     

Epidermal growth factor receptors in plasma membranes of normal and diseased human thyroid glands

We studied the characteristics of epidermal growth factor (EGF) receptors in plasma membrane fractions derived from normal and diseased human thyroid tissues. The mean maximal specific binding of EGF to membrane fractions of normal thyroid tissue (n = 25) was 1.46 +/- 0.47 (+/- SD) fmol/mg protein. The maximal specific binding was higher than the upper limit of the normal range (2.40) in 12 of the 39 (31%) differentiated carcinomas, 2 of the 3 (67%) undifferentiated carcinomas, and 1 squamous cell thyroid carcinoma. In contrast, the maximal specific binding in samples derived from adenomas (1.13 +/- 0.91), adenomatous goiters (0.92 +/- 0.56), and hyperplastic (Graves') thyroids (1.57 +/- 0.61) was not different from that in normal thyroid tissue. Scatchard plot analysis revealed that all thyroid membrane fractions had two classes of specific receptors for EGF. The mean association constant for the high affinity EGF receptors in normal thyroid tissue was 7.9 +/- 2.9 (+/- SD) X 10(9) mol/L-1, and the capacity was 22.9 +/- 7.0 fmol/mg protein. The capacity of the high affinity receptors was higher (P less than 0.05) in differentiated carcinoma (37.2 +/- 25.5) and undifferentiated carcinoma (32.7 +/- 11.6) than in normal thyroid tissue. In one squamous cell carcinoma, the capacities for the two classes of binding sites were about 15-fold greater than in normal thyroid tissue. In contrast, the association constants of the high affinity receptors from carcinomas (differentiated, 6.9 +/- 2.8; undifferentiated, 11.8 +/- 4.1; squamous cell, 8.2) were similar to that of normal thyroid tissue. In the thyroid tissues from eight patients with Graves' disease the capacity of the high affinity binding sites (37.5 +/- 12.3 fmol/mg protein) was higher than that in normal tissue, but the affinity (4.4 +/- 1.6 X 10(9) mol/L-1) was less, and the maximal specific binding was similar in the two types of tissue. These results suggest that a significant increase in the number of high affinity EGF receptors may play a role in the pathogenesis of human thyroid carcinoma.     

Galectin-3: presurgical marker of thyroid follicular epithelial cell-derived carcinomas

Preoperative follicular lesion characterisation represents an unsolved diagnostic problem in thyroid nodular disease. Although fine-needle aspiration biopsy is the most reliable preoperative diagnostic procedure, it shows inherent limitations in differentiating adenoma from follicular carcinoma and, sometimes, follicular variants of papillary carcinoma. Galectin-3 cytoplasmic neoexpression has been proposed as a peculiar feature of thyroid malignant cells, easily detectable in cytological and histological samples. The aim of this study was to re-evaluate the galectin-3 expression in a large sample of thyroid lesions using an immunohistocytochemical biotin-free detection system and a specific anti-human-galectin-3 monoclonal antibody in order to avoid the interference of technical factors, a cause of conflicting results recently reported by some authors. We analysed galectin-3 expression of 39 follicular carcinomas, 26 papillary carcinomas, and 105 adenomas in both cell-block samples and their histological counterparts. All cell-block and histological papillary carcinoma samples showed high levels of galectin-3 immunoreactivity. Thirty-four follicular carcinomas were positive, whereas 5 were negative in cell-blocks but positive in their histological counterparts. Twelve out of 105 adenomas expressed galectin-3 in cell-blocks and histological samples. The diagnostic accuracy of preoperative galectin-3 evaluation in adenomas vs follicular carcinomas was 90.0%. Galectin-3 expression was also investigated in 22 minimally-invasive follicular carcinomas. All of them showed galectin-3 immunoreactivity in both cytological and histological specimens with the exception of two cases, where galectin-3 positivity was observed only in the surgical material. The routine correct use of galectin-3, by increasing the diagnostic accuracy of conventional cytology, improves the management of thyroid nodules and can lead to a sensitive reduction of useless thyroid surgeries.     

甲状腺肿瘤中肝细胞生长因子及其受体蛋白的表达研究

用免疫组化检测甲状腺良恶性肿瘤组织中肝细胞生长因子（HGF）及其受体（c-Met）的表达。结果显示HGF和c-Met蛋白阳性表达率在腺癌组中显著高于腺瘤组，尤其滤泡性腺癌组显著高于滤泡性腺瘤组，二者表达强度在乳头状腺癌组呈显著正相关。提示HGF和c-Met的异常表达可能对甲状腺良恶性肿瘤的鉴别诊断、预后判断有一定参考意义。     

Correlation of cytoplasmic beta-catenin and cyclin D1 overexpression during thyroid carcinogenesis around Semipalatinsk nuclear test site.

The Semipalatinsk nuclear test site (SNTS), the Republic of Kazakhstan, has been contaminated by radioactive fallout. The alteration of oncogenic molecules in thyroid cancer around the SNTS was considered worthy of analysis because it presented the potential to elucidate the relationship between radiation exposure and thyroid cancer. This study aimed to analyze both beta-catenin and cyclin D1 expressions in thyroid carcinomas around the SNTS. We examined nine cases of chronic thyroiditis, eight cases of follicular adenomas, and 23 cases of papillary carcinomas. Immunohistochemically, all carcinomas displayed a strong cytosolic beta-catenin expression, while both chronic thyroiditis and follicular adenomas showed a significantly lower cytoplasmic beta-catenin (22.2% and 37.5%, respectively). No cyclin D1 immunoreactivity was evident in chronic thyroiditis. In contrast, 62.5% of follicular adenomas and 87.0% of papillary carcinoma showed cyclin D1 overexpression. Additionally, a strong correlation between cytoplasmic beta-catenin and cyclin D1 expression was suggested in thyroid tumors. This study revealed a higher prevalence of both aberrant beta-catenin expression and cyclin D1 overexpression in papillary thyroid cancers around the SNTS than sporadic cases. The analysis of the alteration of the Wnt signaling-related molecules in thyroid cancer around the SNTS may be important to gain an insight into radiation-induced thyroid tumorigenesis.     

Differential expression of IgG Fc binding protein (FcgammaBP) in human normal thyroid tissue,thyroid adenomas and thyroid carcinomas

The genetic events involved in thyroid carcinogenesis are still incompletely understood. Several rearrangements and mutations of oncogenes have been implicated in the development of thyroid papillary carcinomas, follicular adenomas and carcinomas. However, none of these molecular alterations is suitable either as a general marker for the diagnosis of thyroid carcinomas or to differentiate between thyroid follicular adenomas and carcinomas. In order to identify new genes with altered expression which could serve as such markers, we analyzed RNA from thyroid tumor and normal tissue using a novel technique called restriction-mediated differential display. Several differentially expressed genes were identified, including the gene for IgG Fc binding protein (FcgammaBP). Differential expression of FcgammaBP was confirmed by quantitative real-time RT-PCR. Our experiments showed that IgG Fc binding protein (FcgammaBP) is differentially expressed in normal thyroid tissue, thyroid adenomas and thyroid carcinomas. While the FcgammaBP gene is constitutively expressed in normal thyroid tissue, its expression is significantly increased in follicular thyroid adenomas and significantly decreased in papillary and follicular thyroid carcinomas. Thus, measurement of the expression levels of FcgammaBP in thyroid biopsies might help to make the otherwise difficult distinction between a thyroid follicular adenoma and a follicular carcinoma.     

Expression of the apical iodide transporter in human thyroid tissues: a comparison study with other iodide transporters

Iodide transport by thyrocytes involves two transporters, namely the Na(+)/I (-) symporter located at the basolateral pole and possibly pendrin in the apical membranes of the cell. Recently, we identified a human gene and its protein product, designated hAIT, as a putative new transporter involved in iodide transfer across the apical membrane of thyrocytes. In the present report, we analyzed both hAIT gene and protein expressions in a large series of benign and malignant human thyroid tissues. Using immunohistochemistry, hAIT staining was detected in normal thyroid tissue in about 10% of follicles; in positive follicles, 10-40% of thyrocytes, mostly the tall cells, were stained. In thyroid tissues obtained from patients with Graves' disease and toxic adenomas, hAIT mRNA and protein levels were similar to those found in normal tissue. In hypofunctioning adenomas, hAIT mRNA levels were slightly decreased, and apical iodide transporter (AIT) immunostaining was similar to that observed in normal thyroid tissue. AIT staining was stronger in Hürthle cell adenomas and in microfollicular adenomas. In thyroid carcinomas, the mean and median hAIT mRNA levels were significantly decreased. Expression of AIT protein was undetectable in most papillary carcinomas and was weak but detectable in most follicular carcinomas; it was negative in anaplastic carcinomas.     

Maspin expression is directly associated with biological aggressiveness of thyroid carcinoma.

Maspin belongs to the serpin superfamily and has been identified as a tumor suppressor because it inhibits cell motility, invasion, and angiogenesis. However, its physiological activity in carcinoma tissues seems to differ according to the origin of the carcinoma. In this study, we investigated maspin expression in thyroid neoplasms originating in follicular cells by means of immunohistochemistry. Neither normal follicular cells nor stromal cells expressed maspin. Follicular adenomas were all negative for maspin, but 12.5% of follicular carcinomas and 30.5% of papillary carcinomas were positive for it. However, the staining pattern was only focal in all positive specimens except for one and maspin-expressing cells were present mainly at the edge of carcinoma nests. Widely invasive follicular carcinomas tended to be more frequently positive for maspin than minimally invasive ones. In papillary carcinoma, maspin expression was directly linked to stage, tumor size, and extrathyroidal invasion. Papillary and follicular carcinomas involving lesions with solid, trabecular, or scirrhous growth patterns (poorly differentiated carcinoma as designated by Sakamoto et al.) expressed maspin in significantly higher incidence than those with pure papillary or follicular patterns. Furthermore, 48.2% of anaplastic (undifferentiated) carcinomas diffusely expressed maspin, and the rest were completely negative. These findings indicate that, in contrast to other carcinomas, maspin expression is directly associated with the biological aggressiveness of thyroid carcinoma. Further studies regarding the function of maspin in this carcinoma are required.     

CD26、Ki67和表皮生长因子受体在甲状腺肿瘤中的表达及其诊断意义

目的 观察CD26、Ki67和表皮生长因子受体(EGFR)在甲状腺良恶性肿瘤中的表达,探讨其鉴别诊断意义,并寻找分化型甲状腺癌标志物.方法 用免疫组化S-P法检测分化型甲状腺癌、腺瘤各50例中CD26、Ki67和EGFR蛋白的表达,并分析它们的相关性.结果 CD26、Ki67和EGFR的阳性表达率、表达强度在腺癌组显著高于腺瘤组、尤其滤泡性腺癌显著高于滤泡性腺瘤组.结论 CD26、Ki67和EGFR的异常表达尤其CD26可能对滤泡上皮起源的甲状腺癌与腺瘤的鉴别诊断、预后判断有参考意义.     

Iodine and cancer.

Thyroid carcinomas are the most frequent endocrine malignancies. Among thyroid carcinomas the most frequent types are the differentiated forms (follicular, papillary or mixed papillary-follicular), whereas anaplastic thyroid carcinoma and medullary thyroid carcinomas are rare. Animal experiments have demonstrated a clear increase in incidence of thyroid epithelial cell carcinomas after prolonged iodine deficiency leading to a situation of the thyroid gland by thyrotropin and possibly other growth factors. However, the overall incidence of differentiated thyroid carcinoma is generally not considered to be influenced by the iodine intake of a population, whereas the distribution of the types of thyroid carcinoma seems to be related to the intake of iodine, with fewer of the more aggressive follicular and anaplastic carcinomas and more papillary carcinomas in iodine rich areas. Populations starting iodine prophylaxis demonstrate an increase in the ratio of papillary to follicular carcinoma. Because a population with higher iodine intake usually has fewer benign nodules in the thyroid gland and the incidence of thyroid carcinomas is similar to an iodine-deficient region, the diagnostic work-up of nodules in the thyroid gland may become affected. The incidence of other cancers, such as breast cancer, may be influenced by the iodine intake, but too few studies are available at present. The present article summarizes available data from both epidemiological studies, animal experiments, and basic gene transfection studies. The overall incidence for a relationship between iodine and cancer is poor and future studies are warranted.     

Immunostaining for Met/HGF receptor may be useful to identify malignancies in thyroid lesions classified suspicious at fine-needle aspiration biopsy.

The receptor for hepatocyte growth factor (Met) is not expressed in the normal thyroid but it is overexpressed in most thyroid carcinomas. We evaluated whether Met immunostaining of cytological smears from fine-needle aspiration biopsy (FNAB) may be useful for the preoperative diagnosis of thyroid cancer. Notably, routine cytological examination often fails to distinguish well-differentiated follicular carcinomas and a proportion of papillary carcinomas (low-grade papillary carcinomas and papillary carcinomas follicular variant [FVPTC]) from benign lesions: all these lesions are usually classified as suspicious. We examined 80 thyroid lesions diagnosed as suspicious at cytology that had subsequently undergone surgery. The histologic diagnosis had been: papillary carcinomas (n = 14), FVPTC (n = 11), follicular carcinomas (n = 25), atypical follicular adenomas (n = 5), follicular adenomas (n = 20), and nodular goiters (n = 5). We also studied typical papillary carcinomas (n = 30) and nodular goiters (n = 10), all correctly diagnosed at cytology. In lesions classified suspicious at routine cytology, Met immunostaining was positive in 12 of 14 (85.7%) papillary carcinomas, 8 of 11 (72.7%) FVPTC, 7 of 25 (28%) follicular carcinomas, and 5 of 5 atypical adenomas. In contrast, none of the 25 lesions cytologically suspicious but benign at histology were positive. These data suggest that Met immunostaining of suspicious cytological smears are useful for identifying malignant lesions, especially those with a papillary histotype.     

Correlation between the loss of thyroglobulin iodination and the expression of thyroid-specific proteins involved in iodine metabolism in thyroid carcinomas

Progress in biotechnology has provided useful tools for tracing proteins involved in thyroid hormone synthesis in vivo. Mono- or polyclonal antibodies are now available to detect on histological sections the Na(+)/I(-) symporter (NIS) at the basolateral pole of the cell, the putative iodide channel (pendrin) at the apical plasma membrane, thyroperoxidase (TPO), and members of the NADPH-oxidase family, thyroid oxidase 1 and 2 (ThOXs), part of the H(2)O(2)-generating system. The aim of this study was to correlate thyroglobulin (Tg) iodination with the presence of these proteins. Tg, T(4)-containing Tg, NIS, pendrin, TPO, ThOXs, and TSH receptor (TSHr) were detected by immunohistochemistry on tissue sections of normal thyroids and various benign and malignant thyroid disorders. Tg was present in all cases. T(4)-containing Tg was found in the adenomas, except in Hurthle cell adenomas. It was never detected in carcinomas. NIS was reduced in all types of carcinomas, whereas it was detected in noncancerous tissues. Pendrin was not expressed in carcinomas, except in follicular carcinomas, where weak staining persisted. TPO expression was present in insular, follicular carcinomas and in follicular variants of papillary carcinomas, but in a reduced percentage of cells. It was below the level of detection in papillary carcinomas. The H(2)O(2)-generating system, ThOXs, was found in all carcinomas and was even increased in papillary carcinomas. Its staining was apical in normal thyroids, whereas it was cytoplasmic in carcinomas. The TSHr was expressed in all cases, but the intensity of the staining was decreased in insular carcinomas. In conclusion, our work shows that all types of carcinomas lose the capacity to synthesize T(4)-rich, iodinated Tg. In follicular carcinomas, this might be due to a defect in iodide transport at the basolateral pole of the cell. In papillary carcinomas, this defect seems to be coupled to an altered apical transport of iodide and probably TPO activity. The TSHr persists in virtually all cases.     

Molecular profiling distinguishes papillary carcinoma from benign thyroid nodules

Recently we identified a molecular basis for differentiating benign and malignant follicular thyroid tumors. The purpose of these studies was to determine whether molecular analysis can be used to differentiate papillary thyroid carcinomas from benign thyroid nodules. Gene expression patterns of 14 papillary thyroid carcinomas and 21 benign tumors were analyzed by oligonucleotide array analysis. The carcinomas included seven classical papillary thyroid carcinomas (PTC) and seven follicular variant of PTC (FVPTC), and the benign tumors included 14 follicular adenomas and seven hyperplastic nodules. A hierarchical clustering analysis was performed to examine the groups for potential differences. The combined PTC and FVPTC groups had a distinct gene expression profile compared with the benign lesions. The sensitivity for a diagnosis of carcinoma was 93%, with a 100% specificity (one FVPTC clustered with the benign nodules). Cancer gene profiles contained both known (Met and galectin-3) and previously unidentified genes. Gene profiling is a reliable means of distinguishing PTC, FVPTC, and benign tumors of the thyroid. These gene profiles may provide insight into the pathogenesis of papillary thyroid carcinoma and may ultimately enhance the preoperative diagnosis of thyroid nodules on a molecular basis.     

Expression of the Na+/I- symporter gene in human thyroid tumors: a comparison study with other thyroid-specific genes.

The expression of 4 thyroid tissue-specific genes [Na+/I- symporter (NIS), thyroid peroxidase (TPO), thyroglobulin (Tg), TSH receptor (TSH-R)] as well as of the glucose transporter type 1 (Glut1) gene was analyzed in 90 human thyroid tissues Messenger ribonucleic acids were extracted from 43 thyroid carcinomas (38 papillary and 5 follicular), 24 cold adenomas, 5 Graves' thyroid tissues, 8 toxic adenomas, and 5 hyperplastic thyroid tissues; 5 normal thyroid tissues were used as reference. A kinetic quantitative PCR method, based on the fluorescent TaqMan methodology and real-time measurement of fluorescence, was used. NIS expression was decreased in 40 of 43 thyroid carcinomas (10- to 1200-fold) and in 20 of 24 cold adenomas (2- to 700-fold); it was increased in toxic adenomas and Graves' thyroid tissues (up to 140-fold). TPO expression was decreased in thyroid carcinomas, but was normal in cold adenomas; it was increased in toxic adenomas and Graves' thyroid tissues Tg expression was decreased in thyroid carcinomas, but was normal in the other tissues. TSH-R expression was normal in most tissues studied and was decreased in only some thyroid carcinomas. In thyroid cancer tissues, a positive relationship was found between the individual levels of expression of NIS, TPO, Tg and TSH-R. No relationship was found with the age of the patient. Higher tumor stages (stages >I vs stage I) were associated with lower expression of NIS (P = 0.03) and TPO (P < 0.01). Expression of the Glut1 gene was increased in 1 of 24 adenomas and in 8 of 43 thyroid carcinomas. In 6 thyroid carcinoma patients, 131I uptake was studied in vivo; NIS expression was low in all samples; 3 patients with normal Glut-1 gene expression had 131I uptake in metastases, whereas the other 3 patients with increased Glut-1 gene expression had no detectable 131I uptake. In conclusion, this study shows 1) a reduced expression of NIS gene in most hypofunctioning benign and malignant thyroid tumors; 2) a differential regulation of the expression of thyroid-specific genes; 3) an increased expression of Glut-1 gene in some malignant tumors that may suggest a role for glucose derivative tracers to detect in vivo thyroid cancer metastases by positron emission tomography scanning.