Adjacent Normal Thyroid Tissue Research Articles

Immunohistochemical evaluation of inflammatory and proliferative markers in adjacent normal thyroid tissue in patients undergoing total thyroidectomy: results of a preliminary study

BackgroundTotal thyroidectomy is the treatment of choice in the majority of thyroid malignancies, preventing the risk of reoperative surgery due to recurrences. In order to assess the usefulness of such an approach, expression levels of inflammatory and proliferative markers were evaluated immunohistochemically in non-lesional adjacent thyroid tissues from a group of patients who underwent total thyroidectomy for different thyroid diseases.MethodsNineteen consecutive patients treated by total thyroidectomy for different thyroid diseases entered the study. IL-6Rb gp130 component of the IL-6 cytokine family members receptor complexes, STAT3 cytokine signalling transduction and transcription activation factor, p53 as tumour suppressor and CK19 cytokeratin as proliferation marker were analyzed in non-lesional thyroid tissues.ResultsGp 130 expression was detected in all tissue samples with a scattered distribution while STAT3 and p53 positivity was observed in 17 out of 19 patients with a prevailing cytoplasmic localization. Cytokeratin 19 positivity was found in patients with papillary carcinoma, in one case of follicular adenoma, 3 multinodular goiters and one Basedow disease.ConclusionBased on the results of this preliminary study, it may be concluded that the presence of a persisting cytokine-mediated activation associated with cytoplasmic localization of p53 is frequently observed in different thyroid diseases. Such a process seems to occur in the thyroid gland as a whole. Moreover, STAT3 activation as well as mutant p53 are risk factors for the development of neoplastic diseases. Total thyroidectomy may be supported as an adequate therapeutic approach for all the patients in whom overexpression of cytokine-dependent markers is detected.

Hyalinizing trabecular tumour of the thyroid—differential expression of distinct miRNAs compared with papillary thyroid carcinoma

To compare the expression pattern of five microRNAs (miRNAs) (146b, -181b, -21, -221, -222) of papillary thyroid carcinoma (PTC) and hyalinizing trabecular tumour of the thyroid (HTT). The expression pattern of five miRNAs known to be up-regulated in PTC was retrospectively analysed in 18 HTTs, adjacent normal thyroid tissue, 10 PTCs, 10 follicular adenomas and 10 non-toxic multinodular goitres (MNG) by reverse transcriptase-polymerase chain reaction using the TaqMan miRNA assay. Furthermore, the two common genetic alterations characteristic for PTC, the V600E mutation of the BRAF gene and RET/PTC 1 and 3 rearrangements, were determined in all HTTs. All miRNAs were significantly up-regulated in PTCs, whereas all miRNAs in HTT, normal thyroid tissue, adenomas, and MNGs were down-regulated. Calculating relative changes in gene expression, a 510-fold change of miRNA 146b between PTC and HTT could be observed followed by fold changes between 6.4 and 29 in the remaining miRNAs (P < 0.001). All HTTs lacked BRAF mutations and RET/PTC rearrangements. Our findings do not support the concept that a high proportion of HTT represents a variant of PTC. It is suggested that HTTs lacking both a miRNA expression pattern characteristic for PTC and RET/PTC rearrangements are re-designated as 'hyalinizing trabecular adenomas'.

Possible Involvement of BRAFV600E in Altered Gene Expression in Papillary Thyroid Cancer

Somatic mutations in BRAF, especially BRAFV600E, are frequently identified in papillary thyroid cancer (PTC) tumors. It has been established that expression levels of numbers of genes are characteristically altered in PTC, however, the link between BRAF mutation and gene expression patterns are still elusive. In the present study, we analyzed relative expression levels of the wild type BRAF and BRAFV600E mRNA by using quantitative PCR (qPCR) and cDNAPCR- RFLP in 19 PTC specimens and adjacent normal thyroid tissues. BRAFV600E mRNA was detected in 17 out of 19 PTC specimens, and the expression levels were valuable among the specimens, suggesting alternative expression of BRAFV600E in each cell and/or alternative population of BRAFV600E-positive clones in the tumor. We then analyzed expression levels of 20 genes by qPCR, and analyzed for possible correlation with expression levels of BRAFV600E mRNA. Expression levels of fibronectin, vimentin and CITED1 (Cbp/p300 interacting protein with glutamic acid and aspartic acid rich carboxyl terminal domain) were positively correlated with those of BRAFV600E, suggesting pathophysiological links between activated BRAF and overexpression of these genes. Among these genes expression of vimentin was decreased by inhibiting BRAF expression in NPA cells that express BRAFV600E by means of siRNA, suggesting activated BRAF positively regulate expression of vimentin. Collectively, our analyses illustrated the possibilities that variable expression of BRAFV600E may modify characters of PTC through its effects on gene expression.

Cytoplasmic Localization of Jab1 and p27Kip1 Might Be Associated with Invasiveness of Papillary Thyroid Carcinoma

p27(kip1) is a well known negative regulator of cell cycle progression. Jab1 directly binds to p27(kip1) and induces nuclear export and subsequent degradation. Recent studies have shown that overexpression of Jab1 and reduced expression of p27(kip1) are associated with advanced tumor stage and poor prognosis in several human cancers. Here, we evaluated 50 papillary thyroid carcinomas (PTC) and adjacent normal thyroid tissue samples by immunohistochemistry for Jab1 and p27(kip1) to elucidate expression levels and subcellular localization. Expression of Jab1 was markedly increased and that of p27(kip1) was reduced in the tumors compared with paired normal samples. Jab1 expression was inversely related to p27(kip1) expression. Jab1 was especially overexpressed within the invasive region compared to center of the tumors. Among clinicopathologic parameters, only tumor size was related with Jab1 (positively) and p27(kip1) expression (negatively) in the invasive region of the tumors. Both Jab1 and p27(kip1) were found predominantly in the cytoplasm of the tumor cells from the invasive regions compared to center of the tumors. The Ki-67 proliferative index was higher in the invasive region than in center of the tumors. A much stronger correlation with the Ki-67 index was noted when both Jab1 and p27(kip1) were simultaneously localized in the cytoplasm than when either Jab1 or p27(kip1) was localized in the cytoplasm alone. These data suggest that in addition to overexpression of Jab1 and reduced expression of p27(kip1), cytoplasmic localization of Jab1 and p27(kip1) are associated with increased cancer cell proliferation and might be related to the invasiveness of PTC.

Evaluation of galectin-8 expression in thyroid tumors

The expression of galectin-8 (gal-8) has been shown to be altered during neoplastic transformation of certain cell types. This is the first study aimed to analyze the expression of this protein in normal and pathological human thyroid tissue. A total of 41 archival thyroid tissue samples (5 follicular adenomas, 31 papillary carcinomas, 5 follicular carcinomas) together with 36 adjacent hyperplastic or normal thyroid tissues were analyzed by immunohistochemistry. Galectin-8 was expressed in the majority of papillary carcinomas (27/31; 87%). Positive but weaker staining was also found in some of the follicular thyroid carcinomas (2/5; 40%) and adenomas (2/5; 40%). This protein was not detectable in five normal thyroid tissue samples, whereas hyperplastic areas adjacent to tumor were weakly positive in 9 out of 31 cases (29%). High gal-8 immunostaining in papillary thyroid carcinoma indicates that gal-8 may potentially serve as a marker of papillary thyroid carcinoma. However, it does not seem to be helpful in the differential diagnostics of follicular carcinoma and adenoma. Further studies are required to determine biological functions and molecular mechanisms underlying the increased expression of gal-8 protein in thyroid lesions, particularly, in papillary thyroid carcinoma.

Seven-year follow-up of a juvenile female with papillary thyroid carcinoma with poor outcome, BRAF mutation and loss of expression of iodine-metabolizing genes

Recent studies reported that BRAF V600E mutation, the most prevalent genetic event found in papillary thyroid carcinoma, is an independent poor prognostic marker. Additionally, it correlates with a less differentiated tumor stage due to reduced expression of key genes involved in iodine metabolism. We previously described a patient with BRAF V600E mutation in primary tumor and a new mutation (V600E+K601del) in the matched-lymph node metastases. In the present study we report an unusual clinical behavior of PTC and correlate with BRAF mutational status and level of expression of TSHR and NIS. Quantitative PCR (qPCR) was used to evaluate the NIS and TSHR level of expression in matched papillary thyroid carcinoma and adjacent normal tissue. In this study, we presented a seven-year follow up of a juvenile papillary thyroid carcinoma patient who had an aggressive tumor harboring BRAF mutation, and failed to conventional therapy. We found a markedly decrease of NIS and TSHR expression in primary PTC compared to adjacent normal thyroid tissue. Our findings suggest that BRAF mutational status and decreased NIS and TSHR expression in this patient may reduce radioiodine uptake and lead to a negative response to radioiodine therapy.

High resolution real time sonography of parathyroid tumors

A total of 15 patients with parathyroid tumours were scanned preoperatively using high-resolution real-time sonography (7 MHz). Of these, 14 had a single adenoma or primary hyperplasia, one had a carcinoma. In 13 out of 15 patients the echogenicity of the parathyroid tumours was consistently less than of the adjacent normal thyroid tissue; in 2 out of 15 cases parathyroid neoplasms were barely distinguishable in echogenicity from thyroid tissue. No specific echomorphologic differences were proved to exist between primary parathyroid hyperplasia, adenoma or carcinoma. The smallest parathyroid neoplasia in this study detected by sonography measured 5 x 8 mm in diameter. The value and limits of parathyroid sonography were discussed with regard to our own experience and the reports in the literature.

NrCAM, a neuronal system cell-adhesion molecule, is induced in papillary thyroid carcinomas

NrCAM (neuron-glia-related cell-adhesion molecule) is primarily, although not solely, expressed in the nervous system. In the present study, NrCAM expression was analysed in a series (46) of papillary thyroid carcinomas (PTCs) and paired normal tissues (NT). Quantitative reverse transcriptase (QRT)-PCR revealed that NrCAM expression was upregulated in all PTCs compared to normal thyroid, whatever the stage or size of the primary tumour. NrCAM transcript levels were 1.3- to 30.7-fold higher in PTCs than in NT. Immunohistochemistry (IHC) confirmed that the expression of NrCAM was considerably higher in tumours (score 2+/3+) than in adjacent normal paratumoural thyroid tissue. The NrCAM protein was detected in all but three (93.3%) PTC samples, and it was mainly cytoplasmic; in some cases there was additional membranous localisation – basolateral and partly apical. In the normal thyroid and tissues surrounding tumours, focal NrCAM immunolabelling was seen only in follicles containing tall cells, where staining was restricted to the apical pole of thyrocytes. Western blot analysis corroborated the QRT–PCR and IHC results, showing higher NrCAM protein levels in PTCs than in paired NT. The level of overexpression of the NrCAM mRNA in tumourous tissue appeared to be independent of the primary tumour stage (pT) or the size of the PTC. These data provide the first evidence that NrCAM is overexpressed in human PTCs at the mRNA and protein levels, whatever the tumour stage. Thus, the induction and upregulation of NrCAM expression could be implicated in the pathogenesis and behaviour of papillary thyroid cancers.

Thyroid transcription factor 1 (TTF-1) and p63 expression in two primary thyroid papillary carcinomas of branchial cleft cysts

Malignant lateral cervical cysts can be related to metastatic tumors or rarely to primary thyroid carcinoma arising in branchial cleft cysts. This study evaluates the expression of thyroid-associated transcription factor-1 (TTF-1) and p63 in three branchial cleft cysts and in two primary thyroid papillary carcinoma of branchial cleft cysts. TTF-1 was negative in the nuclei of the lining epithelia of branchial cleft cysts, but positive in the adjacent normal thyroid tissue, while TTF-1 was positive in the nuclei of the lining epithelia and in the nuclei of the papillae and follicles in branchial cleft cysts with ectopic thyroid carcinoma. P63 was positive in the nuclei of the lining epithelia of branchial cleft cysts, but negative in the adjacent normal thyroid tissue. Papillary thyroid carcinoma of branchial cleft cysts displayed p63-positive foci. In conclusion, our results demonstrate that TTF-1 cannot distinguish between primary and metastatic tumors of branchial cleft cysts. The detection of p63 in papillary thyroid carcinomas of branchial cleft cysts could suggest that p63 contributes to the onset of this tumor. It is really important to evaluate if the case has a metastatic derivation or represents papillary thyroid carcinoma arising in ectopic thyroid tissue in a branchial cleft cyst.

S100A4 (Mts1) gene overexpression is associated with invasion and metastasis of papillary thyroid carcinoma

Tumour cell invasion and metastasis are the hallmark of malignant neoplasm. S100A4 is a member of small calcium-binding protein family and is involved in the cell proliferation and cancer progression. S100A4 is capable of inducing metastasis in animal models and is associated with aggressive phenotype of human tumours. We previously identified S100A4 as a candidate gene involved in anaplastic thyroid cancer metastasis by microarray analysis. To further determine whether S100A4 overexpression is associated with thyroid tumour invasion and metastasis, in the present study, we examined S100A4 gene expression in six benign multinodular goitres (MNG) and 28 matched samples of adjacent normal thyroid tissue (N), primary (T) and metastatic (M) papillary thyroid carcinomas (PTC) by immunohistochemistry and real-time reverse transcription–polymerase chain reaction (RT-PCR) analysis. This gave us the advantage of directly comparing levels of S100A4 expression within the same genetic background. Using immunohistochemistry, we found that high levels of S100A4 were detected in 24 of 28 (86%) PTC specimens and their local regional lymph node or distant metastases. No S100A4 staining was observed in normal thyroid tissues and simple MNG. However, in MNG coexistent with PTC, moderate focal staining could be found in 11 of 15 MNG adjacent to PTC. The S100A4 was stained more intensely in invading fronts than in central portions of both T and M. Real-time RT–PCR analysis of primary tumours and their matched lymph node metastasis demonstrated that significantly higher S100A4 transcripts were present in metastatic tumours as compared to the primary tumours (P<0.01). These data suggest that overexpression of S100A4 is associated with thyroid tumour invasion and metastasis and it may be a potential target for therapeutic intervention.

Ligands for peroxisome proliferator-activated receptor gamma inhibit growth and induce apoptosis of human papillary thyroid carcinoma cells.

Ligands for peroxisome proliferator-activated receptor gamma (PPARgamma) induce apoptosis and exert antiproliferative effects on several carcinoma cell lines. The present study investigates the expression of PPARgamma and the possibility that agonists for PPARgamma also inhibit the growth of human thyroid carcinoma cells. We examined this hypothesis using six cell lines, designated BHP thyroid carcinoma cells, which originated from patients with papillary thyroid carcinoma. RT-PCR analysis revealed that the thyroid carcinoma cell lines BHP2-7, 7-13, 10-3, and 18-21 express PPARgamma. More PPARgamma was expressed in carcinoma than in adjacent normal thyroid tissue in three of six samples of human papillary carcinoma of the thyroid. PPARgamma-positive thyroid carcinoma cells were treated with agonists of PPARgamma, troglitazone, BRL 49653, and 15-deoxy-12,14-prostaglandin J2. Troglitazone (10 micromol/L), BRL 49653 (10 micromol/L), and 15-deoxy-12,14-prostaglandin J2 (1 microg/mL) decreased [(3)H]thymidine incorporation and reduced cell number, respectively, in BHP carcinoma cell lines that expressed PPARgamma. Under low serum conditions, ligands for PPARgamma induced condensation of the nucleus and fragmentation of chromatin into nucleosome ladders. These findings indicate that the death of thyroid carcinoma cells is a form of apoptosis. To investigate the molecular mechanism of the apoptosis, we assessed expression of the apoptosis-regulatory genes bcl-2, bax, and c-myc. Troglitazone significantly increased the expression of c-myc messenger RNA but had no effect on the expression of bcl-2 and bax in thyroid carcinoma cells. These results suggest that, at least in part, the induction of apoptosis in human papillary thyroid carcinoma cells may be due to an increase of c-myc. Troglitazone (500 mg/kg.day) significantly inhibited tumor growth and prevented distant metastasis of BHP18-21 tumors in nude mice in vivo. Taken together, these results suggest that PPARgamma agonist inhibit cell growth of some types of human thyroid cancer.

Expression of the Sodium Iodide Symporter and Thyroglobulin Genes Are Reduced in Papillary Thyroid Cancer

Altered expression of the gene encoding the sodium iodine symporter (NIS) may be an important factor that leads to the reduced iodine accumulation characteristic of most benign and malignant thyroid nodules. Both up- and down-regulation of NIS gene expression have been reported in thyroid cancer using several different methods. The goal of the present study was to accurately identify alterations in NIS gene expression in benign and malignant thyroid nodules using an accurate real-time quantitative RT-PCR assay system. Total RNA was prepared from 18 benign thyroid nodules, 20 papillary thyroid cancers, and 23 normal thyroid samples from 38 subjects. Quantitative RT-PCR was used to measure NIS and thyroglobulin (TG) mRNA expression in normal thyroid tissue and in each nodular tissue sample. Papillary thyroid cancer samples had significantly lower NIS mRNA expression (72 ± 41 picogram equivalents [pg Eq]), than did benign nodules (829 ± 385 pg Eq), or normal tissues (1907 ± 868 pg Eq, P = 0.04). Most important, in the paired samples, NIS gene expression was decreased in each papillary thyroid cancer compared with normal tissue (69% median decrease; range, 40–96%; P = .013). Eleven of the 12 benign nodules also demonstrated lower NIS gene expression than the normal tissue (49% decrease; range, 2–96%; P = .04). Analysis of the paired samples demonstrated that Tg mRNA expression was significantly lower in each of the thyroid cancer samples than in corresponding normal tissue (759 ± 245 pg Eq vs. 1854 ± 542 pg Eq, P = .03). We have demonstrated a significant decrement in NIS gene expression in all papillary thyroid cancers and in over 90% of benign nodules examined compared with adjacent normal thyroid tissue, using a highly accurate quantitative RT-PCR technique. Similarly, thyroid cancers demonstrated significantly lower TG mRNA expression than corresponding normal thyroid. Reduced NIS expression may be an important factor in the impairment of iodine-concentrating ability of neoplastic thyroid tissues.

Expression of galectin-3 in fine-needle aspirates as a diagnostic marker differentiating benign from malignant thyroid neoplasms

Galectin-3 is a beta-galactoside-binding protein that has been reported to be expressed preferentially in thyroid malignancies. The current study was designed to substantiate this finding further and to establish a presurgical diagnostic modality of differentiating between benign and malignant thyroid neoplasms by analyzing galectin-3 expression in fine-needle aspirates. The expression of galectin-3 was examined immunohistochemically in total of 172 specimens: 45 primary and 20 metastatic papillary carcinomas, 8 primary and 2 metastatic follicular carcinomas, 5 primary and 3 metastatic anaplastic carcinomas, 3 primary medullary carcinomas, 25 follicular adenomas, 3 goiters, and 58 adjacent normal thyroid tissue. Alternatively, epithelial cells were isolated from the fine- needle aspirates of 14 thyroid nodules and subjected to immunoblotting analysis of galectin-3. Immunohistochemical analysis revealed that all thyroid malignancies of follicular cell origin (including papillary, follicular, and anaplastic carcinomas) showed high and diffuse expression of galectin-3, whereas one of the three medullary carcinomas of parafollicular cell origin displayed weaker and focal expression of galectin-3. In contrast, neither benign thyroid adenomas, goiters, nor normal thyroid tissues expressed galectin-3. Immunoblot analysis of the isolated epithelial cells detected galectin-3 in nine thyroid nodules that were proven histologically to be malignant ( eight papillary carcinomas and one follicular carcinoma) after surgical intervention, whereas galectin-3 was not detected in five nodules proven to be benign follicular adenomas. Galectin-3 serves as a marker of thyroid malignancy of follicular cell origin. Analysis of galectin-3 expression in fine-needle aspirates enhances the differential diagnostic accuracy between benign and malignant thyroid neoplasms.

Functional insulin receptors are overexpressed in thyroid tumors: is this an early event in thyroid tumorigenesis?

Insulin receptor (IR), a member of the receptor tyrosine kinase family, is expressed in normal thyroid cells and affects thyroid cell proliferation and differentiation. The authors measured IR content in benign and malignant thyroid tumors by three independent methods: a specific radioimmunoassay, 125I-insulin binding studies, and immunohistochemistry. The results obtained were compared with the IR content in paired, adjacent, normal thyroid tissue. To assess IR function in thyroid carcinoma cells, glucose uptake responsiveness to insulin was also studied in a human transformed thyroid cell line (B-CPAP) and in follicular carcinoma cells in primary culture. In 9 toxic adenomas, the average IR content was similar to that observed in the 9 paired normal thyroid tissue specimens from the same patients (2.2+/-0.3 vs. 2.1+/-0.3). In 13 benign nonfunctioning, or "cold," adenomas, the average IR content was significantly higher (P < 0.001) than in paired normal tissue specimens (4.3+/-0.5 vs. 1.8+/-0.1). In 12 papillary and 10 follicular carcinomas, IR content was significantly higher (P < 0.001) than in the adjacent normal thyroid tissue (4.0+/-0.4 vs. 1.6+/-0.2 and 5.6+/-1.0 vs. 1.8+/-0.2, respectively). The finding of a higher IR content in benign "cold" adenomas and in thyroid carcinomas was confirmed by both binding and immunostaining studies. The current studies indicate that 1) IR content is elevated in most follicular and papillary differentiated thyroid carcinomas, and 2) IR content is also elevated in most benign follicular adenomas ("cold" nodules) but not in highly differentiated, hyperfunctioning follicular adenomas ("hot" nodules), which very rarely become malignant. This observation suggests that increased IR expression is not restricted to the thyroid malignant phenotype but is already present in the premalignant "cold" adenomas. It may contribute, therefore, to thyroid tumorigenesis and/or represent an early event that gives a selective growth advantage to transformed thyroid cells.

Telomerase activity in benign and malignant thyroid diseases

Background. Telomerase, an enzyme associated with cellular immortality, is expressed by most malignant cells and is inactive in most normal somatic cells, with the exception of proliferative stem cells, male germ cells, and activated lymphocytes. The measurement of telomerase activity in clinically obtained tissue samples may provide useful information as both a diagnostic and prognostic marker. In this study, we sought to determine whether telomerase activity might prove helpful in the assessment of benign and malignant thyroid tumors. Methods. A modified, semiquantitative polymerase chain reaction-based telomeric repeat amplification protocol assay was used for detection of telomerase activity in 59 samples obtained at thyroidectomy, including 15 thyroid cancers, 22 benign thyroid diseases, and 22 adjacent normal thyroid tissues. Results. Four of 13 differentiated thyroid carcinomas (30%) and 2 of 2 medullary carcinomas (100%) expressed telomerase activity. Unexpectedly, we also detected activity in 3 of 22 (14%) adjacent normal thyroid tissues and 6 of 22 (28%) benign thyroid diseases. Pathologic review of the telomerase-positive benign specimens revealed that many contained extensive lymphoid infiltrates with germinal centers (six of nine, 67%), as did two of four telomerase-positive papillary carcinomas. Conclusions. In contradistinction to other epithelial carcinomas, telomerase does not appear to be fre quently reactivated in differentiated thyroid carcinomas.

Marked increases in cathepsin B and L activities distinguish papillary carcinoma of the thyroid from normal thyroid or thyroid with non-neoplastic disease

Cathepsin B (CB) and cathepsin L (CL) are cysteine endopeptidases involved in the processing of thyroglobulin (Tg) in the normal thyroid. As thyroglobulin expression is frequently altered in thyroid carcinomas, we have analyzed 42 human thyroid tissues from 40 patients to study the effect of malignant transformation an the expression of these endopeptidases. Our samples included 18 cases of papillary carcinoma (of which 10 also had matched adjacent normal thyroid tissue), 6 cases of normal thyroid from autopsy patients, 1 case of follicular carcinoma, 2 cases of medullary carcinoma, 2 cases of follicular adenoma, 3 cases of Hashimoto's thyroiditis (HT) and 10 samples from 8 patients with multi-nodular goiter (MNG). Enzyme-specific activities were increased 15-fold for CB and 9-fold for CL in papillary carcinoma compared with normal adjacent thyroid tissue or normal thyroid from autopsies. CB mRNA content was also markedly increased in papillary carcinoma compared with normal thyroid, primarily due to elevated levels of the 2.2-kb CB mRNA transcript. In thyroids with nonneoplastic diseases, including MNG and HT, there was no significant increase in either CB or CL enzyme activities nor CB mRNA levels compared with normal thyroids from non-cancer cases. Immunohistochemical studies on papillary carcinomas revealed increased CB staining in papillary carcinoma cells, with prominent staining close to the basement membranes of many of the neoplastic cells. Our observations suggest that CB and CL enzyme activities are potentially useful new biochemical markers for distinguishing papillary carcinoma of the thyroid from non-neoplastic thyroid disease.

Expression of the estrogen receptor in human thyroid neoplasms

The expression and quantitation of the estrogen receptor (ER) in human thyroid tumors were examined by biochemical, immunohistochemical, and reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. For this study, neoplasms, adenomatous goiters and adjacent normal thyroid tissues were obtained from 35 patients which included 10 cases of papillary carcinomas, 17 cases of adenomas and 8 cases of adenomatous goiters. Regardless of the histopathological subtype, ER was detected in 19% ( 5 27 ) of the neoplastic tissues with the mean value of ER content of 5.0 ± 1.3 fmol/mg protein and the mean K d value of 0.38 ± 0.28 nM. ER was also detected, but at a lower concentration (2.8 ± 1.6 fmol/mg protein), in the surrounding normal tissues. There was no significant difference between the neoplasms and adenomatous goiters with respect to the incidence of ER positivity and ER content. Furthermore, ER-positive specimens, as determined by both biochemical and immunohistochemical techniques, also showed the expression of ER mRNA detected by RT-PCR method. These results demonstrate that both ER mRNA as well as ER protein are expressed in thyroid neoplasms. This suggests the possibility that estrogen may affect the tumorigenesis or the progression of some thyroid neoplasms.

Increased binding capacity of receptors for the epidermal growth factor in benign thyroid nodules and thyroid malignancies

To determine the role of epidermal growth factor (EGF) receptors in thyroid tumorigenesis, EGF binding was compared in membranes from malignant and from benign thyroid tumors. Surgical specimens were obtained from 28 patients with thyroid carcinomas (3 papillary, 13 follicular, 6 undifferentiated, and 6 medullary carcinomas) and from 30 patients with benign thyroid tumors (15 scintigraphically functional and 15 nonfunctional nodules). In 30 cases normal tissue adjacent to the tumor was also obtained. EGF binding was seen to be increased not only in thyroid carcinomas but also in benign thyroid tumors, particularly in functional thyroid adenomas. The highest EGF binding was found in undifferentiated carcinomas. A direct comparison of the EGF binding characteristics in tumor and adjacent normal thyroid tissue revealed that the increased binding of EGF is due mainly to an increase in the number of binding sites rather than an alteration in receptor affinities. EGF binding capacities were 18.4 +/- 16.7 fmol/mg protein in thyroid carcinomas and 10.5 +/- 5.2 fmol/mg in the corresponding normal tissue (P < 0.05, Kd 0.84 +/- 0.26 nM, n = 11). In autonomously functioning thyroid adenomas binding capacities were 14.2 +/- 8.2 fmol/mg in the nodules and 8.9 +/- 4.8 fmol/mg in normal tissue (P < 0.01, Kd 0.73 +/- 0.62 nM, n = 15). In conclusion, EGF receptor levels are increased not only in malignant thyroid tumors but also in well-differentiated benign thyroid nodules.(ABSTRACT TRUNCATED AT 250 WORDS)

Manganese superoxide dismutase content and localization in human thyroid tumours.

Manganese-containing superoxide dismutase (Mn-SOD) content and its immunohistochemical localization in human thyroid tumours and some other thyroid diseases were examined and compared with adjacent normal thyroid tissue. Enzyme-linked immunosorbent assay (ELISA) was used in this study for the measurement of Mn-SOD. The content of Mn-SOD tended to increase in diffuse hyperplasia, adenomatous goitre, and follicular adenoma. In papillary carcinoma, it was significantly higher than in adjacent normal thyroid tissue. Follicular carcinoma also revealed a markedly high Mn-SOD content. In the immunohistochemical study, adjacent normal thyroid tissue showed granular positive staining of Mn-SOD in the cytoplasm. An increase of Mn-SOD was observed in the papillary proliferative lesion of diffuse hyperplasia and in the follicles adjacent to lymphoid tissue in chronic thyroiditis with hypothyroidism. Strong positive staining of Mn-SOD was observed in papillary and follicular carcinomas, whereas in anaplastic carcinoma staining was markedly less intense. These results indicate that the Mn-SOD content varies according to the degree of differentiation of thyroid carcinomas.

Modification of the amounts of G proteins and of the activity of adenylyl cyclase in human benign thyroid tumours.

The possibility that a TSH post-receptor-binding defect is responsible for the pathogenesis of benign thyroid tumours was studied. Thus, we attempted to determine in hyperfunctioning (hot) nodules and non-functioning (cold) nodules whether the functional activity or the amount of G proteins were modified in comparison with surrounding normal tissues. The adenylyl cyclase response to agonists that bypass the TSH-receptor complex (forskolin, guanosine 5'- (beta.gamma-imido)triphosphate (Gpp(NH)p) or [AIF4]-) was studied on membranes from tumorous and adjacent normal thyroid tissues. We also examined the ability of G proteins to be ADP-ribosylated by cholera toxin (CT) or pertussis toxin (PT), and quantified G proteins by Western blot analysis with specific antisera directed against Gs alpha and Gi alpha subunits. Basal adenylyl cyclase activity was unchanged in hot tumours compared with normal tissue whereas the stimulation of adenylyl cyclase by Gpp(NH)p or [A1F4]- (which act directly on Gs) as well as by forskolin (which acts on the catalyst) was significantly (P less than 0.05) decreased in five of seven nodules studied. Two types of response were found in cold nodules, depending upon whether they were microfollicular or macrofollicular tumours. Basal as well as stimulated adenylyl cyclase activity was increased (0.02 less than P less than 0.05) in microfollicular tumours. In contrast, in macrofollicular tumours basal adenylyl cyclase was unchanged whereas stimulated adenylyl cyclase activity was decreased (0.02 less than P less than 0.05). The ability of Gs or Gi to be ADP-ribosylated by CT or PT respectively was maintained in tumorous tissue.(ABSTRACT TRUNCATED AT 250 WORDS)