Neoplastic Human Thyroid Tissue Research Articles

Down-Regulation of miR-218-2 and Its Host Gene SLIT3 Cooperate to Promote Invasion and Progression of Thyroid Cancer

The functional relationships between intronic microRNAs (miRNAs) and their host genes in thyroid cancer remain unclear. miR-218, a miRNA down-regulated in several kinds of cancers and associated with multiple cancer phenotypes, is transcribed from 2 loci located on chromosomes 4p15.31 (miR-218-1) and 5q35.1 (miR-218-2) within the introns of SLIT2 and SLIT3, respectively. The aim of our work was to investigate the expression and the roles of miR-218-1 and miR-218-2, as well as their host genes SLIT2 and SLIT3 in thyroid carcinogenesis. The expression of miR-218-1 and miR-218-2, as well as their host genes SLIT2 and SLIT3, in a panel of normal and neoplastic human thyroid tissues was assessed by quantitative RT-PCR. We restored the expression of miR-218-2 and SLIT3 in thyroid cancer cells and evaluated their effects on cell invasion, migration, and proliferation. We found that miR-218-2 and its host gene SLIT3 were down-regulated concomitantly in thyroid cancer. Synergistic inhibitory effects of miR-218-2 with SLIT3 on thyroid cancer cell invasion, migration, and proliferation were observed. Moreover, the effects of miR-218-2 on thyroid cancer cells were due, at least partially, to targeting PDGFRA and PLCG1. These results implicate the involvement of miR-218-2 and its host gene SLIT3 in thyroid cancer cell invasion, migration, and proliferation. Our findings highlight the functional associations of intronic miRNAs and their host genes in thyroid carcinogenesis.

Expression of prolactin receptor and prolactin in normal and malignant thyroid: A tissue microarray study

There is increasing evidence involving prolactin (PRL) and its receptor (PRLR) in the development of different cancers. The aim of the present study was to investigate the expression of PRLR and PRL in human thyroid tissues. Using tissue microarray (TMA) by immunohistochemical staining, we examined the expression level of PRLR and PRL in 314 specimens from 71 thyroid cancer patients and 15 normal thyroid samples. Expression of the PRLR was observed in 93.3% of normal thyroid samples and in 76.1% of all thyroid cancers, while expression of PRL was observed in only 10% of medullary thyroid carcinomas and not at all in the other specimens, whether normal or neoplastic. Moreover, results suggested an overexpression of PRLR in 70% of medullary thyroid carcinomas, whereas 53.3% of poorly differentiated thyroid carcinomas showed a negative pattern of staining (p = 0.014 vs normal). Present data revealed, for the first time, a widespread expression of PRLR in normal and neoplastic human thyroid tissues as well as a scarce expression of PRL, observed only in a few medullary thyroid carcinomas. Whether the overexpression of PRLR observed in medullary thyroid carcinomas or the underexpression of PRLR observed in poorly differentiated thyroid carcinomas play a contributory role in the oncogenesis of these tumors remains to be determined.

Id1 Gene Expression Is Up-Regulated in Hyperplastic and Neoplastic Thyroid Tissue and Regulates Growth and Differentiation in Thyroid Cancer Cells

The Id (inhibitor of DNA binding) proteins are a family of helix-loop-helix (HLH) proteins (Id1, Id2, Id3, and Id4) that lack the basic domain necessary for DNA binding. The Id1 protein enhances cell proliferation and inhibits cellular differentiation in a variety of cell types. We have previously demonstrated that the Id1 gene is up-regulated in papillary and medullary thyroid cancers. In this study we characterized the expression and distribution of the Id1 protein in normal, hyperplastic, and neoplastic human thyroid tissue. We also evaluated the effect of the Id1 gene on thyroid cancer cell growth and markers of thyroid cell differentiation. We used semiquantitative immunohistochemistry to characterize Id1 protein expression in normal, hyperplastic (multinodular goiter and Graves' disease), and neoplastic thyroid tissue from 103 patients. Normal thyroid tissue had the lowest level of Id1 protein expression (P < 0.0001). Anaplastic thyroid cancer had the highest level (vs. benign and malignant thyroid tissues, P < 0.01). Id1 protein expression was higher in malignant thyroid tissue than in hyperplastic thyroid tissue (P < 0.02). We found no significant association between the level of Id1 protein expression and patient age, sex, tumor-node-metastasis stage, tumor size, primary tumor vs. lymph node metastasis, primary tumor vs. recurrent tumors, and extent of tumor differentiation. Inhibiting Id1 mRNA expression in thyroid cancer cell lines using Id1 antisense oligonucleotides resulted in growth inhibition (P < 0.03) and decreased thyroglobulin and sodium-iodine symporter mRNA expression (P < 0.02). In conclusion, Id1 is overexpressed in hyperplastic and neoplastic thyroid tissue and directly regulates the growth of thyroid cancer cells of follicular cell origin, but is not a marker of aggressive phenotype in differentiated thyroid cancer.

Localization and expression of thyroid hormone receptors normal and neoplastic human thyroid.

The aim of this study was to investigate the regional expression of thyroid hormone nuclear receptor forms (TR(alpha) and TR(beta)) and isoform (TR(alpha1) and TR(beta2)) mRNAs in normal and neoplastic (benignant and malignant) human thyroid tissue. Tumor specimens from patients with thyroid carcinomas (papillary: 5 cases; follicular: 5 cases; anaplastic: 2 cases), thyroid follicular adenomas (7 cases) and tissue from normal thyroid glands (12 cases) were analyzed by in situ hybridization and semiquantitative RT-PCR for the expression of TR(alpha1) and beta, as well as for the isoform alpha2 that does not bind the hormone. In normal tissues, TR(alpha2) was expressed at lower levels compared to TR(alpha1) (alpha1/alpha2 = 4.3). In papillary and follicular carcinomas, the expression of TR(alpha1) and TR(beta) did not change as compared with normal thyroid tissue and adenomas (0.87 +/- 0.15 SD vs 0.89 +/- 0.17 densitometric units, DU, and 0.15 +/- 0.02 vs 0.14 +/- 0.03 DU, respectively). However, the expression of TR(alpha2) was significantly higher in differentiated carcinomas compared to normal thyroid tissue and adenomas (0.47 +/- 0.05 vs 0.20 +/- 0.05 DU, p < 0.05) with alpha1/alpha2 = 1.4. In anaplastic carcinoma all TRs were absent. We concluded that both normal and pathological thyroid tissues, with the exception of anaplastic carcinoma, express all TRs in thyreocites and that differentiated thyroid carcinomas are associated in enhancing the expression of TR(alpha2) mRNA.

Telomerase activity in surgical specimens and fine-needle aspiration biopsies from hyperplastic and neoplastic human thyroid tissues

Background Telomerase activity (TA) indicates malignancy, but activated lymphocytes also express TA. Correlation between TA in thyroid tissues and fine-needle aspiration (FNA) samples and knowledge about TA in adjacent tissue are of importance. Methods The telomeric repeat amplification protocol assay followed by enzyme-linked immunosorbent assay detection was performed on 78 thyroid cases including 53 suspected malignancies, preoperative and perioperative FNA specimens, and adjacent tissue. Results Benign lesions in cancer-suspected cases were TA negative. Eight of 13 papillary (62%) and 4 of 5 follicular (80%) tumors were TA positive (TA+). Lower TA was observed in conventional papillary cancer than in follicular, tall cell variant of papillary and anaplastic cancers. Adjacent tissues with lymphocyte infiltration were TA+ in 9 of 17 cases (53%). Nine of 65 adjacent tissues (14%) were TA+. Three of 6 preoperative and 9 of 11 perioperative FNA samples from malignant tumors corresponded to the tissue TA. Conclusions High TA may reflect more severe thyroid cancer. Telomerase activity in FNA biopsies does not add reliable diagnostic information, and presence of lymphocytes can give false-positive results.

Specific binding sites for synthetic growth hormone secretagogues in non-tumoral and neoplastic human thyroid tissue.

The presence of specific receptors for synthetic growth hormone secretagogues (GHSs) has been investigated in non-tumoral and neoplastic human thyroid tissue using a radio-iodinated peptidyl GHS ((125)I-labelled Tyr-Ala-hexarelin) as ligand. Specific binding sites for Tyr-Ala-hexarelin were detected in membranes from non-tumoral and follicular-derived neoplastic thyroid tissue, but not in thyroid tumours (medullary carcinomas) of parafollicular (C cell) origin. The binding activity was greatest in well differentiated neoplasms (papillary and follicular carcinomas), followed by poorly differentiated carcinomas, non-tumoral thyroid parenchyma, follicular adenomas and anaplastic carcinomas. Both peptidyl (Tyr-Ala-hexarelin, hexarelin, growth hormone releasing peptide (GHRP6) and non-peptidyl (MK 0677) GHSs completely displaced the radioligand from binding sites of non-tumoral thyroid gland, but MK 0677 was significantly less potent. The IC(50) values were (1. 9+/-0.3)x10(-8) mol/l for Tyr-Ala-hexarelin, (2.1+/-0.2)x10(-8) mol/l for hexarelin, (2.4+/- 0.3)x10(-8) mol/l for GHRP6 and only (1. 5+/-0.4)x 10(-7) mol/l for MK 0677. Similar IC(50) values were found in neoplastic thyroid tissue. Scatchard analysis of the binding revealed a finite number of binding sites in non-tumoral (B(max): 1232+/-32 fmol/mg protein, n=3) and neoplastic (papillary carcinomas) thyroid tissue (B(max): 2483+/-380 fmol/mg protein, n=5), with dissociation constants (K(d)) of (3.8+/-0.3)x10(-9) and (4. 4+/-0.6)x 10(-9) mol/l, respectively. On the basis of this evidence, we investigated the effects of some GHS on the proliferation of three different human follicular thyroid carcinoma cell lines (NPA, WRO and ARO) in which the presence of specific GHS receptors was also demonstrated. Tyr-Ala-hexarelin, GHRP6 and MK 0677 were able to inhibit serum-stimulated [(3)H]thymidine incorporation in NPA cells at concentrations close to their binding affinity. These substances also caused a significant inhibition of cell proliferation, which was evident at the earliest time of treatment (24 h) in all the cell lines, and at the latest time (96 h) in NPA cells only. In conclusion, this paper confirms the existence of specific binding sites for GHS in normal thyroid tissue and demonstrates, for the first time, that these binding sites are present in papillary and follicular carcinomas, low in anaplastic carcinomas and absent in medullary carcinomas of the thyroid. This work also provides evidence of a growth-inhibitory effect of GHS on cell lines derived from follicular thyroid cancers.

Mutations of the adenomatous polyposis coli gene in sporadic thyroid neoplasms.

Several epidemiological studies have demonstrated an association between familial adenomatous polyposis coli (FAP) and thyroid neoplasms. Predisposition to FAP is conferred by mutations in the APC gene, located on chromosome 5q21. Somatic mutations of APC are also observed in about 60% of sporadic colorectal adenomas and carcinomas, suggesting that disruption of this putative tumor suppressor gene may play a role in both familial as well as acquired colorectal tumorigenesis. The APC gene is expressed in normal human thyroid, thyroid adenomas, and differentiated carcinoma tissues as well as in four clonal human thyroid carcinoma cell lines, as demonstrated by reverse transcriptase-polymerase chain reaction of a 388-base APC messenger ribonucleic acid fragment spanning exons 14 and 15, followed by hybridization to an exon 15-specific complementary DNA probe. Eighty human thyroid neoplasms were examined for loss of heterozygosity of the APC locus, using primers flanking a hypervariable dinucleotide (CA) repeat (CB26) immediately adjacent to the APC gene. Of 71% informative samples, 2 showed allelic loss: a follicular adenoma (FA) and a nodule from a multinodular goiter (MNG). The DNA of 83 benign and malignant thyroid neoplasms and 4 thyroid carcinoma cell lines was examined for mutations within a 1200-basepair stretch of exon 15 by single strand conformation polymorphism. Five sets of overlapping primers were used for PCR. The anaplastic thyroid carcinoma cell line (ARO) had 1 APC allele with an adenine insertion at codon 1556 (ACTA to AACTA), leading to a premature stop codon at 1558. An anaplastic carcinoma had a mutation of codon 1346 (TCA-CCA; Ser to Pro). In summary, the APC gene is expressed in normal and neoplastic human thyroid tissue and is a target for inactivating mutations in some thyroid tumors.

Expression of thyrotropin receptor and thyroid hormone receptor messenger ribonucleic acid in normal, hyperplastic, and neoplastic human thyroid tissue.

In the first part of this study, we examined TSH receptor (TSHR) and thyroid hormone receptor (T3R beta) messenger ribonucleic acid (mRNA) levels in normal, hyperplastic, and neoplastic human thyroid tissue. Tumor specimens from patients with different thyroid carcinomas and thyroid adenomas, and tissues from patients with Graves' disease and from normal thyroid glands were analyzed by solution hybridization and Northern blot using complementary RNA probes. In the second part of the study, mRNA analysis of T3R was extended to include the expression levels of each of the four T3R isoforms alpha 1, alpha 2, beta 1, and beta 2. In neoplastic thyroid tissue such as papillary and follicular carcinomas, the expression of both TSHR and T3R beta mRNA per microgram total RNA was significantly lower than that in normal thyroid tissue. The decrease in T3R beta mRNA was shown to represent a specific and significant decrease in T3R beta 2 mRNA levels in particular, but also in the expression levels of T3R beta 1 mRNA. No differences were found in the expression levels of T3R alpha 1 or -alpha 2 mRNA. Furthermore, no differences in TSHR or T3R mRNA levels were found in thyroid tissue from patients with Graves' disease compared to normal thyroid tissue. It is concluded that the reduction of TSHR and T3R mRNA in specific neoplastic thyroid tissues might be associated with the differentiation state of these tumors and that the decrease in T3R mRNA levels is due to a specific decrease in the expression levels of the T3R beta gene.

Expression of thyrotropin receptor and thyroid hormone receptor messenger ribonucleic acid in normal, hyperplastic, and neoplastic human thyroid tissue

Expression of thyrotropin receptor and thyroid hormone receptor messenger ribonucleic acid in normal, hyperplastic, and neoplastic human thyroid tissue

Isolation of a cDNA whose expression is markedly increased in malignantly transformed FRTL cells and neoplastic human thyroid tissues.

We have cloned a cDNA whose mRNA levels are increased in malignantly transformed rat thyroid FRTL cells (FRTL-Tc cells). We constructed a cDNA library from FRTL-Tc cells in lambda gt10 and screened the cDNAs by differential plaque filter hybridization. Twenty-five thousand clones were screened and one cDNA (C140) was selected which corresponded to a mRNA whose expression was 5.8 times higher in FRTL-Tc cells than in FRTL cells. A 0.8 kb specific C140 mRNA was detected by Northern blot analysis of FRTL-Tc and FRTL mRNAs. The C140 cDNA was sequenced and found to encode a protein of 227 amino acids. We have found that C140 mRNA is conserved in human thyroid cells, but it is encoded by a smaller 0.7 kb transcript. C140 mRNA was highly expressed in neoplastic thyroid tissues and weakly in normal thyroid tissues in the same patients. Additionally, we found that C140 mRNA was also increased in the thyroid tissue of a patient with Graves' disease. These results suggest that C140 expression might be higher in rapidly growing thyroid cells than in normal cells, and might provide a new aspect for the study of thyroid tumours.

Thyroid-stimulating hormone activates phospholipase C in normal and neoplastic thyroid tissue.

Thyroid-stimulating hormone (TSH) stimulates thyroid growth through two signal transduction pathways: the G protein-adenylate cyclase system and the G protein-phospholipase C (PLC) system. The adenylate cyclase system has been studied extensively, but there is little information available concerning PLC activity in thyroid neoplasms. Human thyroid membranes were incubated for 30 minutes at 37 degrees C in the presence or absence of bovine TSH (300 mU/ml). PLC activity was assayed by liberation of inositol phosphates from the enzymatic hydrolysis of tritiated phosphatidylinositol bisphosphate. Fifty-six tissues were assayed (normal, 23; multinodular goiter, 5; follicular adenoma, 9; and differentiated thyroid cancer, 19 [9 low risk and 10 high risk]). TSH significantly increased PLC activity in normal, benign, and most malignant thyroid neoplasms. Although there were no differences in basal or TSH-stimulated PLC activity between the groups of normal thyroid, multinodular goiter, follicular adenoma, or the cancers, one half of the high-risk cancers had an aberrant PLC response. This is the first demonstration that TSH stimulates PLC activity in normal and neoplastic human thyroid tissue. Aberrant TSH-stimulated PLC activity was present in half of the aggressive thyroid neoplasms.

Increased phospholipase C activity in neoplastic thyroid membrane.

The phospholipase C (PLC)-protein kinase C (PKC) signal transduction pathway appears to be important for cellular growth of many normal and neoplastic tissues. Because alterations in the thyroid-stimulating hormone (TSH) receptor-adenylate cyclase-protein kinase A system in some thyroid tumors do not correlate with tumor size, invasiveness, or metastatic potential, we studied the PLC activity in both normal and neoplastic thyroid tissues from 11 patients. Five of these patients had follicular adenomas and 6 had papillary carcinomas. An 8,000 x g membrane fraction and a 105,000 x g cytosol fraction were prepared from the normal and neoplastic human thyroid tissues. PLC hydrolyzes phosphatidylinositol, 4,5-diphosphate (PIP2) to diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3). Phospholipase C activity was determined measuring the hydrolysis of [3H]-PIP2. The activity of PLC in the neoplastic thyroid tissue membrane fraction (20.91 +/- 2.28 nmol PIP2 hydrolyzed/mg protein/120 min) was higher than that in normal thyroid membrane (14.27 +/- 0.82) (p < 0.05). In contrast, PLC activity was similar in the neoplastic (16.12 +/- 0.86 nmol PIP2 hydrolyzed/mg protein/120 min) and normal (16.66 +/- 0.60) cytosol. There was no difference between PLC activity in the membrane fraction from adenomas (21.21 +/- 3.71 nmol PIP2 hydrolyzed/mg protein/120 min) when compared with thyroid carcinomas (20.67 +/- 3.14). Neoplastic thyroid membranes have greater PLC activity than that found in normal thyroid membranes from the same patients. Although PLC activity in benign and malignant thyroid membranes was similar, the increased PLC activity in thyroid neoplasms may be responsible for or contribute to the enhanced growth of some thyroid tumors.

Effect of somatostatin on adenylate cyclase activity in normal and neoplastic thyroid tissue.

Thyroid stimulating hormone (TSH) and other substances increase adenylate cyclase (AC) activity and growth of normal and neoplastic thyroid tissue. Factors that inhibit cAMP may provide targeted therapy to tumors dependent on cAMP for growth. Somatostatin has been reported to inhibit the growth of gastrinomas and carcinoid tumors. We therefore studied the effects of somatostatin on basal, TSH, pertussis toxin, and forskolin stimulated adenylate cyclase activity in normal and neoplastic thyroid tissue from 19 patients. Adenylate cyclase (AC) activity was determined by the conversion of alpha 32P-ATP to 32P-cAMP in pmoles/mg protein/30 minutes in an 8000 x g particulate fraction rich in thyroid plasma membranes. TSH (300 mU/ml) and forskolin (100 mM) (a diterpine that directly stimulates the catalytic unit of AC) increased AC activity in normal and neoplastic thyroid tissue. The AC stimulation was greater in the neoplasms (p less than 0.01). Somatostatin (5 x 10(-6)M) decreased basal and TSH stimulated AC activity below basal levels in both normal and neoplastic thyroid tissue (including papillary, follicular, and medullary carcinomas). The inhibition of AC by somatostatin was greater in neoplastic tissue (p less than 0.025). Pertussis toxin (which blocks the inhibitory guanyl nucleotide regulatory protein) was able to partially reverse the effect of somatostatin. Somatostatin partially inhibited forskolin stimulated AC activity. Somatostatin inhibits basal and TSH stimulated AC activity in both normal and neoplastic human thyroid tissue, with a greater effect on neoplasms. These studies establish that somatostatin blocks a major regulator of thyroid growth and provides the rationale for the use of somatostatin analogs in the treatment of thyroid cancers.

Beta 2-adrenergic receptor mRNA is overexpressed in neoplastic human thyroid tissues.

The expression of beta 2-adrenergic receptor (AR) mRNA was investigated in normal and neoplastic human thyroid tissues. A combination of techniques for reverse transcribing mRNA into cDNA and the incorporation of 32P-gamma ATP into the polymerase chain reaction (PCR)-generated fragments allowed us to detect beta 2-AR mRNA in surgically excised thyroid specimens. The levels of beta 2-AR cDNA generated by PCR in thyroid adenomas and cancers were 3.3 and 6.9 times, respectively, as high as that of normal thyroid tissues. These findings suggest that the level of beta 2-AR mRNA is correlated with the extent of differentiation in neoplastic tissues. The present study provides new insights into the relationships between the AR-adenylate cyclase system and the regulation of the growth and differentiation in neoplastic human thyroid tissues.

Expression of the thyroid hormone receptor, the oncogenes c-myc and H-ras, and the 90 kD heat shock protein in normal, hyperplastic, and neoplastic human thyroid tissue.

Expression of the thyroid hormone receptor (TR beta), the 90 KD heat shock protein (HSP 90), and the oncogenes H-ras and c-myc mRNA in normal hyperplastic, and neoplastic human thyroid tissue was investigated by Northern blot and slot blot analyses. The TR beta mRNA was present in all normal and neoplastic thyroid tissue samples. The levels were significantly higher in normal and hyperplastic tissues (7.91 +/- 0.48 and 7.60 +/- 0.68 arbitrary units, respectively) than in neoplastic tissues (3.82 +/- 0.67) (p < 0.001). H-ras and c-myc mRNA were also detected in glandular tissue specimens, but no significant difference was observed in their expression levels. Furthermore, there was a tendency to a negative correlation between the level of TR beta and c-myc mRNA (p = 0.06). In normal thyroid tissue, HSP 90 mRNA levels were significantly higher than in hyperplastic and papillary carcinoma tissue specimens (p < 0.001). These results indicate that mRNA of TR beta and HSP 90 (the latter only in papillary thyroid carcinoma) are expressed in relation to the degree of cellular differentiation. Furthermore, the presence of TR beta in normal thyroid tissue implies that T3 and T4 may be involved in the regulation of their own production via TR beta activated feedback mechanism(s).

Beta 2-adrenergic receptor mRNA is overexpressed in neoplastic human thyroid tissues

Beta 2-adrenergic receptor mRNA is overexpressed in neoplastic human thyroid tissues

Immunohistochemical study of thyroid peroxidase in normal, hyperplastic, and neoplastic human thyroid tissues

An immunohistochemical study using two monoclonal antibodies (MoAb 30 and MoAb 47) against thyroid peroxidase (TPO) was performed on surgical specimens of human thyroid carcinoma (n = 65), adenoma (n = 70) and Graves' disease (n = 10). Normal adjacent thyroid tissue was used as positive control. Monoclonal antibody 30 reacted significantly with all adenoma and most carcinoma, whereas MoAb 47 reacted with 66 adenoma but only two carcinoma. Of the four adenomas that did not react with MoAb 47, three were of the fetal type. Both carcinoma reacting with MoAb 47 were of the well-differentiated follicular type. These findings further confirm the hypothesis that thyroid carcinoma is associated with changes in the quantity and antigenic properties of TPO. Although the alterations in antigenic behavior revealed by MoAb 47 are not 100% specific, they may allow more accurate diagnosis of malignancy in thyroid tumors.

The mRNA levels of thyrotropin receptor, thyroglobulin and thyroid peroxidase in neoplastic human thyroid tissues

Expression levels of thyrotropin receptor (TSH-R), thyroglobulin (Tg) and thyroid peroxidase (TPO) mRNA in normal and neoplastic human thyroid tissues (6 adenomas and 7 carcinomas) were investigated by Northern-blot and slot-blot analyses. We found that TSH-R mRNA levels were significantly lower in carcinoma tissues than in normal tissues. The levels of Tg mRNA were also significantly lowered in adenoma and carcinoma tissues as compared to normal tissues. In contrast, no significant difference was observed in the expression levels of TPO mRNA between these tissues. Furthermore, TSH-R mRNA levels were well-correlated with Tg mRNA levels in neoplastic tissues. These results suggest that mRNAs of TSH-R and Tg are expressed in relation to their degree of differentiation.

Epidermal growth factor receptors and adenylate cyclase activity in human thyroid tissues

Thyroid stimulating hormone (TSH) and epidermal growth factor (EGF) are growth factors for some thyroid cells in cultures. We have previously found more EGF receptors in neoplastic human thyroid tissues than in normal thyroid tissues. We have also found a higher TSH-stimulated adenylate cyclase (AC) activity in neoplastic human thyroid tissues than in normal thyroid tissues. To clarify the relationship between the effect of EGF and TSH on thyroid tissue, we measured the binding of EGF and TSH and the basal, TSH-stimulated and forskolin-stimulated adenylate cyclase activity in 49 normal, hyperplastic and neoplastic human thyroid tissues (5 normal, 2 Hashimoto thyroiditis, 5 Graves' disease, 14 multinodular goiters, 9 follicular adenomas, 5 follicular carcinomas, 8 papillary carcinomas, and 1 undifferentiated carcinoma). Specific binding of EGF and TSH were measured by radioreceptor assays using competitive inhibition of radio-labeled ligand by unlabeled ligand. Basal, maximally (300 mU/ml) TSH-stimulated, and maximally (100 mM) forskolin-stimulated adenylate cyclase activities were also measured in the same membrane particulate fractions from the thyroid tissues. We found: neoplastic thyroid tissues bind more labeled EGF than nonneoplastic thyroid tissues; follicular adenomas and carcinomas have higher EGF binding than other thyroid tissues; a weak but significant correlation between specific EGF binding and specific TSH binding, and between specific EGF binding and TSH-stimulated adenylate cyclase activity of the thyroid membrane preparations. These findings are consistent with the hypothesis that TSH stimulates an increase in thyroid EGF receptors by increasing intracellular cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Estrogen receptor in normal and neoplastic human thyroid tissue

Clinical evidence suggests the possible influence of estrogen on the biologic behavior of thyroid neoplasm. In this study we evaluated the distribution and characteristics of intracellular receptors for estrogen in normal and neoplastic thyroid tissue obtained from 54 patients. Forty-two percent of all specimens assayed by the protamine sulfate precipitation technique had a detectable intracellular binding site for estrogen. Differentiated carcinomas (eight of eight) and adenomas (seven of nine) had high incidences of receptors compared with goiter (five of 23) and normal thyroid (three of eight). However, there were no detectable receptors for estrogen in medullary carcinomas of the thyroid (0 of six). Also, carcinomas and adenomas had higher receptor contents than did goiter and normal differentiated thyroid tissue. There was no significant difference in the affinity of estrogen for receptors among the different histologic groups. There were both 4S and 8S receptor types, which were specific for estrogen. The binding of estrogen to thyroid tissue and differentiated neoplasm originating from thyroid tissue were comparable to the binding of estrogen to other hormone-dependent normal and neoplastic tissues.