Immunohistochemical analysis of estrogen receptors in 313 paraffin section cases of human thyroid tissue

Associations between artificial light at night and risk for thyroid cancer: A large US cohort study

BACKGROUND

Light at night (LAN) inhibits nighttime secretion of melatonin and may cause circadian disruption, which may be a risk factor for cancer. Recent studies have linked high LAN exposure with elevated breast cancer risk. Given that breast cancer may share a common hormone-dependent etiology with thyroid cancer and that circadian rhythms play a role in regulating thyroid function, the authors hypothesized that exposure to LAN is positively associated with thyroid cancer incidence.

METHODS

This study examined the association between LAN and thyroid cancer incidence in the National Institutes of Health-American Association of Retired Persons Diet and Health Study. LAN exposure was estimated from satellite data and was linked to residential addresses at the baseline. Incident thyroid cancer cases were ascertained via linkage to state cancer registries. Cox regression was used to determine the relationship between LAN and thyroid cancer risk, with adjustments made for sociodemographic, lifestyle, and other environmental factors.

RESULTS

Among 464,371 participants, a positive association was found between LAN and thyroid cancer risk. Specifically, in comparison with the lowest quintile of LAN, the highest quintile was associated with a 55% increase in risk (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.18-2.02). The association was primarily driven by papillary thyroid cancer and was stronger in women (HR, 1.81; 95% CI, 1.26-2.60) than men (HR, 1.29; 95% CI, 0.86-1.94). In women, the association was stronger for localized cancer, whereas in men, the association was stronger for a more advanced stage. Results were consistent across different tumor sizes.

CONCLUSIONS

LAN was positively associated with thyroid cancer risk. Future studies are needed to confirm this association and identify underlying biological mechanisms.

Immunohistochemical Expression of Estrogen Receptor-α and Progesterone Receptor in Patients with Papillary Thyroid Cancer

BACKGROUND

Papillary thyroid cancer (PTC) prevalence is nearly 3 times higher in females than in males. This gender difference suggests that growth and progression of PTC might be influenced by female sex hormones.

OBJECTIVES

To analyze the expression of both estrogen receptor (ER)-α and progesterone receptor (PR) by immunohistochemistry in 203 PTC patients.

METHODS

ER-α and PR expression was evaluated in paraffin-embedded tumor tissue samples of 45 males and 158 females followed up for 7.2 ± 3.7 years.

RESULTS

ER-α was expressed in 52 (25.6%) patients (41 females and 11 males) and PR in 94 (46.3%) patients (75 females and 19 males). ER-α and PR were coexpressed in 31 (15.3%) patients (27 females and 4 males). ER-α expression correlated significantly with tumor size in the whole sample (ER-α positive 22.8 ± 11.8 mm vs. ER-α negative 15.1 ± 12.4 mm; p = 0.02) and in the subgroup of women (ER-α positive 18.8 ± 12.8 mm vs. ER-α negative 14.9 ± 12.3 mm; p = 0.048). In addition, ER-α expression significantly correlated with remission of the disease. In fact, of the 192 patients followed up, 50/153 (32.7%) disease-free patients were ER-α positive, in contrast to only 3/39 (7.7%) with evidence of disease persistence/recurrence (χ² = 8.5, p = 0.0036). PR expression was not associated with any of the parameters analyzed.

CONCLUSIONS

The present study confirmed recent data indicating that ER-α and PR expression is a common finding in thyroid tumor tissue. However, in contrast to previous reports, we observed an association between ER-α expression and a more favorable outcome in PTC patients.

Expression of estrogen and progesterone receptors across human malignancies: new therapeutic opportunities

Estrogen and progesterone receptors (ERs and PRs) are known for their prognostic as well as treatment predictive value in breast cancer. Although these receptors are differentially expressed in some other malignancies, and likely participate in the biology of those cancer types, the relevance to outcome and therapy is not well established. The use of ER as a highly effective therapeutic target in oncology was pioneered in breast cancer, and the lessons learned from its success could potentially benefit patients with several other malignancies in which hormone receptors are highly expressed. Indeed, there are several potent drugs available that target hormone receptors. These agents show incontrovertible evidence of benefit in patients with hormone receptor-positive breast cancer. It is conceivable that these drugs may have salutary effects in a variety of cancers other than those originating in the breast, based on the overexpression of hormone receptors in some patients, and the preclinical and clinical reports showing responses to these drugs in diverse cancers, albeit in small series or anecdotally. We therefore undertook a literature review in order to summarize the current data regarding the biologic and clinical implications of expression of estrogen and progesterone receptors in various malignancies and the possibilities for deployment of hormone manipulation beyond breast cancer.

Anti-tumor efficacy of fulvestrant in estrogen receptor positive gastric cancer

To investigate the prognostic role of the estrogen receptor (ER) in gastric cancer (GC) patients, tumor tissues from 932 patients with advanced GC were assessed for ER expression using immunohistochemistry, and their clinicopathologic features were evaluated. Forty patients (4.3%) had ER expression and they were more frequently associated with diffuse type gastric cancer and shorter disease free survival. Furthermore, we carried out in vitro analysis to evaluate the effect of ER modulation on the proliferation of GC cell lines. Estradiol enhanced proliferation of ER positive GC cells while it did not show any effect on ER negative GC cells. When ER was inhibited by fulvestrant and ER siRNA, estradiol-induced proliferation of ER positive GC cell was suppressed. Paclitaxel showed synergistic anti-proliferative impacts with fulvestrant. Suppressing ER by fulvestrant, paclitaxel and ER siRNA showed increased expression of E-cadherin, which is a crucial factor in diffuse-type carcinogenesis.

Estrogen and its role in thyroid cancer

Proliferative thyroid diseases are more prevalent in females than in males. Upon the onset of puberty, the incidence of thyroid cancer increases in females only and declines again after menopause. Estrogen is a potent growth factor both for benign and malignant thyroid cells that may explain the sex difference in the prevalence of thyroid nodules and thyroid cancer. It exerts its growth-promoting effect through a classical genomic and a non-genomic pathway, mediated via a membrane-bound estrogen receptor. This receptor is linked to the tyrosine kinase signaling pathways MAPK and PI3K. In papillary thyroid carcinomas, these pathways may be activated either by a chromosomal rearrangement of the tyrosine receptor kinase TRKA, by RET/PTC genes, or by a BRAF mutation and, in addition, in females they may be stimulated by high levels of estrogen. Furthermore, estrogen is involved in the regulation of angiogenesis and metastasis that are critical for the outcome of thyroid cancer. In contrast to other carcinomas, however, detailed knowledge on this regulation is still missing for thyroid cancer.

Sexual dimorphism and thyroid dysfunction: a matter of oxidative stress?

Thyroid diseases, such as autoimmune disease and benign and malignant nodules, are more prevalent in women than in men, but the mechanisms involved in this sex difference is still poorly defined. H₂O₂ is produced at high levels in the thyroid gland and regulates parameters such as cell proliferation, migration, survival, and death; an imbalance in the cellular oxidant-antioxidant system in the thyroid may contribute to the greater incidence of thyroid disease among women. Recently, we demonstrated the existence of a sexual dimorphism in the thyrocyte redox balance, characterized by higher H₂O₂ production, due to higher NOX4 and Poldip2 expression, and weakened enzymatic antioxidant defense in the thyroid of adult female rats compared with male rats. In addition, 17β-estradiol administration increased NOX4 mRNA expression and H₂O₂ production in thyroid PCCL3 cells. In this review, we discuss the possible involvement of oxidative stress in estrogen-related thyroid pathophysiology. Our current hypothesis suggests that a redox imbalance elicited by estrogen could be involved in the sex differences found in the prevalence of thyroid dysfunctions.

Anti-thyroid cancer properties of a novel isoflavone derivative, 7-(O)-carboxymethyl daidzein conjugated to N-t-Boc-hexylenediamine in vitro and in vivo

The incidence of thyroid cancer is up to 3 folds higher in women than in men, suggesting that estrogenic effects may be involved in the pathogenesis of this malignancy. Here, we explore whether or not human thyroid cancer cell growth can be curbed by a novel isoflavone derivative generated in our laboratory, the N-t-Boc-hexylenediamine derivative of 7-(O)-carboxymethyl daidzein (cD-tboc). With the exception of the follicular cancer cell line WRO, estrogen receptor (ER)α mRNA was only marginally expressed in cell lines derived from papillary (NPA), follicular (MRO), anaplastic thyroid carcinoma (ARO) such that the expression of estrogen receptor (ER) βmRNA was more abundant than that of ERα mRNA in these cell types. Estradiol-17β (E2; 0.03-300nmol/l) per se increased proliferation in all four cell-types. The ERβ-specific agonist DPN increased [(3)H]-thymidine incorporation in all four thyroid cancer cell lines, whereas the ERα-specific agonist PPT increased growth only in NPA and WRO. By contrast, cD-tboc, derived from the weak estrogen daidzein, did not cause cell growth and dose-dependently diminished cell growth in all four cell lines via apoptosis and not necrosis, as detected by the release of histone-DNA fragments. The cytotoxic growth inhibitory effect of cD-tboc in these cells was modulated by E2 and the general caspase inhibitor Z-VAD-FMK, and the magnitude of this salvage was cell type-and dose-dependent. When nude mice carrying ARO thyroid xenografts were treated with cD-tboc, tumor volume decreased significantly, and no apparent toxicity was observed. These results suggest that cD-tboc may be a promising agent for therapy of thyroid carcinoma either alone or in combination with existing cytotoxic drugs.

Role of estrogen in thyroid function and growth regulation

Thyroid diseases are more prevalent in women, particularly between puberty and menopause. It is wellknown that estrogen (E) has indirect effects on the thyroid economy. Direct effects of this steroid hormone on thyroid cells have been described more recently; so, the aim of the present paper was to review the evidences of these effects on thyroid function and growth regulation, and its mechanisms. The expression and ratios of the two E receptors, α and β, that mediate the genomic effects of E on normal and abnormal thyroid tissue were also reviewed, as well as nongenomic, distinct molecular pathways. Several evidences support the hypothesis that E has a direct role in thyroid follicular cells; understanding its influence on the growth and function of the thyroid in normal and abnormal conditions can potentially provide new targets for the treatment of thyroid diseases.

Clinicopathological and molecular characterization of nine cases of columnar cell variant of papillary thyroid carcinoma

The majority of papillary thyroid carcinoma is indolent and associated with long-term survival. The columnar cell variant, however, is a rare subtype that is variable in biological behavior; some are clinically aggressive, whereas others are more clinically indolent. Tumor size, tumor circumscription, and encapsulation may influence the behavior of columnar cell carcinomas. Other variables including genetic changes and putative biomarkers associated with malignant growth have not been thoroughly examined in these neoplasms. In this study, nine cases of columnar cell variant of papillary thyroid carcinoma from three institutions were classified as clinically indolent or aggressive based on pathological features, clinical history, and outcome. Indolent tumors were typically small, circumscribed or encapsulated, and from younger female patients, whereas aggressive tumors were large, locally aggressive, associated with regional and distant metastasis, and from older male patients. The missense mutation, V600E in the BRAF oncogene (BRAF(V600E)), was detected in three of nine of cases, of which two were clinically aggressive. Immunohistochemical evaluation of neoplasia-associated markers showed increased nuclear cyclin D1 expression, elevated Ki-67 proliferation indices, and predominantly weak nuclear p53 staining in both indolent and aggressive tumors. Expression of β-catenin was largely restricted to a membranous pattern in both tumor types. Cytoplasmic expression of bcl-2 was overall mildly reduced in indolent neoplasms. Nuclear expression of estrogen and progesterone receptors was increased in both indolent and aggressive neoplasms, but was without sex- or age-related differences; however, whereas progesterone receptor expression was diffuse and strong in clinically indolent carcinomas, its expression was diminished in aggressive neoplasms. Recognition of the clinicopathological characteristics and the molecular and immunophenotypic features of the columnar cell variant of papillary thyroid carcinoma may aid in characterizing neoplasms that behave indolently or aggressively.

Gender differences in thyroid cancer: a critical review

It has long been known that the incidence of thyroid cancer in women is significantly higher than that in men. The objective of this article is to review gender differences in thyroid cancer, as well as epidemiological, clinical and experimental research on the role of sex hormones, their receptors and other molecular factors in this well-established thyroid cancer gender discrepancy. Although more common in women, thyroid cancer typically presents at a more advanced stage and with a worse disease prognosis in men. Clinical evidence on the impact of estrogen and other sex hormones on thyroid cancer has remained inconclusive, although numerous experimental studies have suggested that these hormones and their receptors may play a role in tumorigenesis and tumor progression. Studies of thyroid cancer cell lines suggest that an imbalance between the two estrogen receptor (ER) isoforms, α and β, may be responsible for the cell proliferation seen with estrogen treatment. Expression studies on thyroid tumors indicate that they express ER and possibly progesterone receptors and androgen receptors, but there is conflicting evidence as to whether or not there is a difference in receptor status between thyroid cancers, benign thyroid lesions and normal thyroid tissue. There have been few studies evaluating the ERα/ERβ profiles in thyroid tumors and normal thyroid tissue. Our understanding of the underlying basis for sex differences in thyroid cancer has improved over the last few decades, but the relationship between gender and thyroid cancer risk has remained elusive. Areas for future research include ERα/ERβ profiling of normal and neoplastic thyroid tissue, association between ER status and tumor dedifferentiation, and evaluation of the signaling pathways by which estrogen and other sex steroids exert their effects on thyroid cancer cells. Sex steroid receptors, and then downstream signaling pathways, represent promising future therapeutic targets for thyroid cancer treatment, and further study is required.

Clinical and molecular features of differentiated thyroid cancer diagnosed during pregnancy

OBJECTIVE

Pregnancy represents a favorable condition for the development of thyroid nodules, likely due to the secretion of hormones with stimulatory activity. In particular, differentiated thyroid cancer (DTC) represents the second most frequent tumor among those diagnosed during pregnancy. However, few and discordant data are available about the impact of pregnancy on tumor outcome.

METHODS

A total of 123 women with DTC were divided into three groups according to the timing of tumor diagnosis (group 1, at least 1 year after the delivery; group 2, during pregnancy or in the first year after delivery; and group 3, before pregnancy or nulliparity) and evaluated according to the international guidelines. Furthermore, immunohistochemical studies of estrogen receptor alpha (ERalpha) were performed in 38 papillary thyroid cancer tissues from the three groups.

RESULTS

Thyroid cancer diagnosed during pregnancy was associated with a poorer prognosis compared to tumors developed in nongravidic periods (P<0.0001). Accordingly, at the stepwise logistic regression analysis, the diagnosis of DTC during pregnancy or in the first year post partum was the most significant indicator of persistent disease (P=0.001). Interestingly, ERalpha expression significantly differed among tumors of the three groups, being detected in 31% of group 1, in 87.5% of group 2, and in 0% of group 3 (P=0.01).

CONCLUSIONS

Present data indicate that pregnancy has a negative impact on the outcome of thyroid cancer. The presence of ERalpha in the majority of tumors diagnosed during pregnancy indicates that the poorer outcome of these cases could be related to the estrogen-mediated growth stimulus.

Oestrogen mediates the growth of human thyroid carcinoma cells via an oestrogen receptor-ERK pathway

OBJECTIVES

Although thyroid cancer occurs much more frequently in females, the role of sex hormones in thyroid carcinogenesis is unknown. In this study, it has been investigated how 17beta-oestradiol (E2) influenced proliferation and growth of thyroid cancer cells.

MATERIALS AND METHODS

Cell proliferation and its related molecules were examined in thyroid papillary carcinoma cells (KAT5), follicular thyroid carcinoma cells (FRO) and anaplastic carcinoma cells (ARO). Levels of oestrogen receptor (ER) alpha and beta were regulated by their agonists (PPT and DPN), antagonists and siRNA.

RESULTS

E2 promoted cell proliferation. Such an effect was positively related to ERalpha but negatively to ERbeta; PPT enhanced cell proliferation while DPN inhibited it. PPT increased Bcl-2 expression while DPN decreased it. DPN also elevated Bax expression. PPT elevated the level of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2), suggesting a positive role of ERK1/2 in E2-induced cell proliferation. Knockdown of ERalpha significantly attenuated E2-mediated Bcl-2 and pERK1/2 expression. In contrast, knockdown of ERbeta markedly enhanced them.

CONCLUSIONS

Oestrogen stimulates proliferation of thyroid cancer cells, associated with increase in Bcl-2 and decrease in Bax levels in an ERK1/2-related pathway. Imbalance between ERalpha and ERbeta may contribute to thyroid carcinogenesis.

Glucocorticoid receptor subunit gene expression in thyroid gland and adenomas

The present study was undertaken to investigate whether the glucocorticoid receptor -alpha (GR-alpha) and -beta (GR-beta) mRNA may be expressed in thyroid gland. Ten normal thyroid gland and 14 follicular adenomas were studied using a real-time fluorescent quantitative RT-PCR (FQ-RT-PCR) method. The results demonstrated that there was a lower expression of GR-alpha mRNA (x10(6) GR-alpha cDNA copies/microg total RNA) in thyroid adenoma (1.27+/-0.26) than that in normal thyroid gland (3.53+/-1.22) (p < 0.001). The expression of GR-beta mRNA was lower in all the thyroid tissues. Of note, there was a significant difference in GR-beta mRNA expression (x10(4) GR-beta cDNA copies/microg total RNA) between thyroid adenoma (80.8+/-13.9) and thyroid gland (1.78+/-0.59) (p < 0.001). The GR-alpha/GR-beta ratios in thyroid adenoma and normal thyroid gland were 1.67+/-0.68 and 207.57+/-84.41 respectively (p < 0.001). These results revealed, for the first time, that both GR-alpha and GR-beta mRNA expression were detectable in both thyroid gland and adenomas tissues. We therefore conclude that down-regulation of GR-alpha and up-regulation of GR-beta mRNA expression may play an important role in the thyroid adenomas.

Estrogen receptor (ER)-beta, but not ER-alpha, is present in thyroid vessels: immunohistochemical evaluations in multinodular goiter and papillary thyroid carcinoma

OBJECTIVE

Estrogen receptors (ERs) have been demostrated in the vessel structures of several systems. Little is known on the presence of ERs in the thyroid vessels.

DESIGN

We immunohistochemically evaluated both ER-alpha and ER-beta immunoreactivity (IR) in both vascular and follicular thyroid cells in tissue samples from 17 cases of multinodular goiter (MNG) and 17 cases of papillary thyroid carcinoma (PTC).

MAIN OUTCOME

ER-alpha IR was undetectable in either tissue examined. In 100% of MNG samples, nuclear ER-beta IR was detected in both endothelial and follicular cells. In PTC samples, endothelial nuclear ER-beta IR was found in 100% of cases, whereas the nuclear staining of follicular cells was found in 83% of cases. The intensity of staining of the endothelial ER-beta IR was comparable between MNG and PTC. However, when follicular cells were considered, a tendency toward a decrease in nuclear staining and a significant increase in cytoplasmic staining were found in PTC lesions as compared to MNG.

CONCLUSIONS

This study demonstrated that ER-beta, but not ER-alpha, IR is present in the endothelium of thyroid vessels. Furthermore, although data need to be confirmed in larger observations, these results suggest the lack of differences in the pattern of vascular ER-beta IR between MNG and PTC.

Anaplastic Thyroid Carcinoma: Expression Profile of Targets for Therapy Offers New Insights for Disease Treatment

BACKGROUND

Anaplastic thyroid cancer is an endocrine malignancy. Its rare and rapidly lethal disease course has made it challenging to study. Little is known regarding the expression by anaplastic tumors of molecular targets for new human anticancer agents that have been studied in the preclinical or clinical setting. The objective of this work was to evaluate the expression profile of anaplastic thyroid tumors for molecular targets for treatment.

METHODS

Of the 94 cases of anaplastic thyroid cancers diagnosed and treated in British Columbia, Canada over a 20-year period (1984-2004), 32 cases (34%) had adequate archival tissue available for evaluation. A tissue microarray was constructed from these anaplastic thyroid tumors and immunohistochemistry was utilized to evaluate expression of 31 molecular markers. The markers evaluated were: epidermal growth factor receptor (EGFR), HER2, HER3, HER4, ER, PR, uPA-R, clusterin, E-cadherin, beta-catenin, AMF-R, c-kit, VEGF, ILK, aurora A, aurora B, aurora C, RET, CA-IX, IGF1-R, p53, MDM2, p21, Bcl-2, cyclin D1, cyclin E, p27, calcitonin, MIB-1, TTF-1, and thyroglobulin.

RESULTS

A single tumor with strong calcitonin expression was identified as a poorly differentiated medullary carcinoma and excluded from the study cohort. The mean age of the anaplastic cohort was 66 years; 16 patients (51%) were females, and the median patient survival was 23 weeks. A wide range in molecular marker expression was observed by the anaplastic thyroid cancer tumors (0-100%). The therapeutic targets most frequently and most strongly overexpressed by the anaplastic tumors were: beta-catenin (41%), aurora A (41%), cyclin E (67%), cyclin D1 (77%), and EGFR (84%).

CONCLUSIONS

Anaplastic thyroid tumors exhibit considerable derangement of their cell cycle and multiple signal transduction pathways that leads to uncontrolled cellular proliferation and the development of genomic instability. This report is the first to comprehensively evaluate a panel of molecular targets for therapy of anaplastic thyroid cancer and supports the development of clinical trials with agents such as cetuximab, small-molecule tyrosine kinase inhibitors, and aurora kinase inhibitors, which may offer new hope for individuals diagnosed with this fatal thyroid malignancy.

Induction of thyroid papillary carcinoma cell proliferation by estrogen is associated with an altered expression of Bcl-xL

PURPOSE

One of the features of thyroid carcinoma is its predilection for women of reproductive age relative to men. An increased risk has also been documented in women who have used estrogens for gynecologic reasons. The aim of this study was to explore the mechanism by which sex hormones contribute to the development of thyroid carcinoma, which is not well understood at present.

MATERIALS AND METHODS

In this study, we investigated the effects of estradiol and testosterone on cell proliferation in a human thyroid papillary carcinoma cell line (KAT5) by MTT assay. We also studied the expression of estrogen receptors and the levels of anti-apoptotic Bcl-xL protein, pro-apoptotic Bax protein, and messenger RNA in the cells by Western blot and reverse transcriptase polymerase chain reaction analysis.

RESULTS

The results showed that estradiol promotes cell proliferation when compared with cells treated with testosterone and untreated cells, and that the growth-promoting effect of estradiol was attenuated by tamoxifen. The expression of Bcl-xL was markedly increased in a dose-dependent manner, resulting in an elevated ratio of Bcl-xL to Bax.

DISCUSSION

We conclude that estradiol promotes KAT5 cell proliferation and that the underlying mechanism may be associated with up-regulation of Bcl-xL expression. The data provide insight into the molecular mechanism underlying the epidemiologic data that shows a two- to threefold increased prevalence of thyroid carcinoma in women relative to men. From the therapeutic point of view, the finding that estradiol enhances anti-apoptotic signaling pathways may be significant in the search for novel prevention and treatment strategies of thyroid carcinomas.

Chronic Estradiol Exposure Modulates Thyroid Structure and Decreases T4 and T3 Serum Levels in Middle-Aged Female Rats

OBJECTIVES

In human medicine, estrogen is applied in prevention and treatment of health problems associated with the menopause. The aim of this study was to examine the effects of chronic estradiol dipropionate (EDP) treatment on thyroid gland structure and function in middle-aged female rats.

METHODS

At 14 months of age, Wistar rats received 0.625 mg EDP/kg b.w./day intraperitoneally for 2 weeks. The peripheral and central zones of the thyroid were stereologically analyzed and the following morphometric parameters determined: volume density of follicles, follicular epithelium, interstitium and colloid, epithelial height and the index of activation rate. Serum levels of TSH, T4 and T3 were determined by ELISA.

RESULTS

EDP treatment led to significant decreases in volume densities of follicles and follicular epithelium, epithelial height and index of activation rate (by 11%, p < 0.05; 23%, p < 0.005; 11%, p < 0.05 and 21%, p < 0.05, respectively) in comparison to control values. Hyperplasia of thyroid follicular cells was noticed in 25% of EDP-treated animals. Serum levels of T4 and T3 were decreased (by 33%, p < 0.005 and 28%, p < 0.001, respectively), but TSH concentration was not significantly different from that of the controls.

CONCLUSION

Chronic estradiol treatment significantly decreased volume density and height of centrally located follicular epithelium, follicular activation index and serum level of total thyroid hormones in middle-aged rats.

Estrogen receptors (alpha and beta) and 17beta-hydroxysteroid dehydrogenase type 1 and 2 in thyroid disorders: possible in situ estrogen synthesis and actions

Both epidemiological and experimental findings suggest the possible roles of sex steroids in the pathogenesis and/or development of various human thyroid disorders. In this study, we evaluated the expression of estrogen receptors (ER) alpha and beta in normal thyroid glands (N = 25; female: n = 13, male: n = 10, unknown: n = 2) ranging in age from fetus to adult. Furthermore, using immunohistochemistry, we investigated the expression of ERalpha and beta in 206 cases of thyroid disorders, including 24 adenomatous goiters, 23 follicular adenomas, and 159 thyroid carcinomas. In addition, we also studied the mRNA expression of ERalpha and beta and 17beta-hydroxysteroid dehydrogenase Type 1 and 2, enzymes involved in the interconversion between estrone and estradiol, using reverse transcription polymerase chain reaction (RT-PCR), in 48 of these 206 cases (10 adenomatous goiters, 10 follicular adenomas, and 28 papillary thyroid carcinomas) in which fresh frozen tissues were available for examination to further elucidate the possible involvement of intracrine estrogen metabolism and/or actions in thyroid disorders. ERalpha labeling index, or percentage of cells immunopositive for ERalpha, was significantly higher in adenomatous goiter (14.2 +/- 6.4), follicular adenoma (13.4 +/- 5.1), and thyroid carcinoma (16.4 +/- 2.1) than in normal thyroid gland (0; P <.05). Few follicular cells were positive for ERalpha in normal thyroid glands. In papillary carcinoma, ERalpha labeling index was significantly higher in premenopausal women (28.1 +/- 4.5) than in postmenopausal women (14.2 +/- 2.9) and in men of various ages (7.6 +/- 2.7; P <.05). In other histological types of thyroid carcinoma, no significant correlations were detected. ERbeta immunoreactivity was detected in both follicular and C-cells of normal thyroid glands, including those in developing fetal thyroid glands. In addition, ERbeta immunoreactivity was detected in the nuclei of various thyroid lesions. But no significant correlations were detected between ERbeta labeling index and clinicopathological findings including age, menopausal status, gender, and/or histological type of thyroid lesions. 17beta-hydroxysteroid dehydrogenase Type 1 expression was detected in 31/48 (64.0%) of the cases examined, whereas Type 2 was detected only in 3/46 (6.3%) of all the cases examined. These results demonstrated that estrogens may influence the development, physiology, and pathology of human thyroid glands, and these effects, especially through ERalpha, may become more pronounced in neoplasms, particularly in papillary carcinoma arising in premenopausal women.

Dose-threshold for thyroid tumor-promoting effects of orally administered kojic acid in rats after initiation with N-bis(2-hydroxypropyl) nitrosamine

In order to evaluate the threshold dose of thyroid tumor-promoting effects of KA, male F344 rats were initiated with N-bis(2-hydroxypropyl) nitrosamine (DHPN; 2000 mg/kg body wt., single s.c. injection) and, starting 1 week later, received pulverized basal diet containing 0%, 0.002%, 0.008%, 0.03%, 0.125%, 0.5% or 2%KA for 20 weeks. Five rats each in the 0%, 0.125%, 0.5% and 2%KA groups were sacrificed at week 12, and 10 rats each in all groups at week 20. As an additional experiment, three groups without DHPN initiation received basal diet, a diet containing 0.5% or 2%KA for 20 weeks. The serum T4 levels were significantly decreased in the DHPN-initiated groups given 0.125%KA or more at week 12. No significant decreases in serum T3 levels were observed in the groups treated with DHPN + KA and a significant increase was evident in the 2%KA-alone group at week 20. Some rats in the DHPN + 2%KA group at weeks 12 and 20 and the 2%KA-alone group at week 20 showed pronounced elevation of serum TSH. Thyroid weights were significantly increased in the DHPN-initiated groups receiving 0.5% and 2%KA at weeks 12 and 20 and in the 2%KA-alone group at week 20. Histopathologically, the incidences of focal thyroid follicular cell hyperplasias in the DHPN-initiated groups treated with 0.125%, 0.5% and 2%KA at week 20 were 5/10, 10/10 and 8/8 rats, respectively. At week 20, adenomas were observed in 7/10 rats in the DHPN + 0.5%KA group and 8/8 rats in the DHPN + 2%KA group, and carcinomas were observed in 6/8 rats in the DHPN + 2%KA group. In the groups without DHPN initiation, only focal follicular cell hyperplasia was observed in 1/9 rats in the 2%KA-alone group. These results suggest that the no-observed-adverse effect for the thyroid tumor-promoting effect of KA is 0.03% (15.5 mg/kg/day) under the present experimental conditions, and that KA possesses weak tumorigenic activity in rats due to continuous serum TSH stimulation by a non-genotoxic mechanism.

Estradiol increases proliferation and down-regulates the sodium/iodide symporter gene in FRTL-5 cells

Goiter (increased thyroid gland size) is more prevalent in women than men, even in areas where iodine levels in the diet are sufficient. We investigated a possible role of estrogen on thyroid follicular cell growth using rat FRTL-5 thyroid follicular cells as a model. Estrogen receptor-alpha (ERalpha) messenger RNA was present in FRTL-5 cells using a RT-PCR assay and was confirmed by Western blot analysis. An estrogen-responsive reporter gene was transfected into FRTL-5 cells to test the functionality of the endogenous ERs. Estradiol increased the activity of the reporter gene, and the antagonist, ICI182780, inhibited ER-dependent transcription. To extend this analysis, we examined the effect of estradiol on FRTL-5 cell growth. Estradiol increased FRTL-5 cell growth in a time- and concentration-dependent manner in either the absence or presence of TSH. Because iodine is known to inhibit thyroid cell growth, the effect of estradiol on the expression of the sodium/iodide symporter (NIS) was assessed as a potential target of estrogen action. Estradiol blocked TSH-induced NIS expression, and treatment of cells with estradiol and ICI182780 restored TSH-induced NIS expression to normal levels. These data demonstrate that FRTL-5 cells contain functional ERs that enhance cell growth and inhibit expression of the NIS. The demonstration of a direct effect of estradiol on thyroid follicular cells raises the possibility that it may play a role in the sexually dimorphic prevalence of goiter.

Axillary lymph node calcification due to metastatic papillary carcinoma

A case is presented in which calcification in an axillary lymph node seen on a screening mammogram was the presenting feature of metastatic papillary carcinoma, presumed to be of thyroid origin. The differential diagnosis of axillary lymph node calcification seen on mammography is reviewed.

No association between immunohistochemical expression of p53, c-erbB-2, Ki-67, estrogen and progesterone receptors in female papillary thyroid cancer and ionizing radiation

An association has previously been reported between exposure to medical diagnostic ionizing radiation and papillary thyroid cancer in women. To further evaluate potential mechanisms in carcinogenesis, the expression of p53, c-erbB-2, as well as Ki-67, estrogen and progesterone receptors were analyzed by immunohistochemistry in 19 women exposed to X-rays and for comparison in nine women without such reported exposure. They all had papillary thyroid cancer. No difference was found between these groups. The results of this study showed that p53, c-erbB-2, Ki-67, estrogen and progesterone receptors are not involved in papillary thyroid cancer associated with exposure to medical diagnostic ionizing radiation.

Establishment of a rat thyroid carcinoma cell line in vitro demonstrating high DNA synthesis in response to insulin-like growth factor I

We previously established transplantable rat thyroid carcinoma cell lines in vivo from primary thyroid tumors induced by N-bis-(2-hydroxypropyl)nitrosamine (DHPN). In the present study, an insulin-like growth factor I (IGF-I)-responsive cell line (TRTC-G1-C-A4) in culture was derived from one (well differentiated papillary type) of these carcinoma cell lines G1. TRTC-G1-C-A4 cells were found to exhibit specific saturable binding of IGF-I with a Kd of 1.16 nM at approximately 43.6 fmol/10(5) cells. Inclusion of IGF-I (10 and 50 ng/ml) in the culture medium resulted in a significant increase of [3H]thymidine incorporation and marked cell proliferation. IGF-II (10 ng/ml) and insulin (1 microgram) produced no such effects. The molecular weight of IGF-I receptors on the cell membrane was determined by Western blotting analysis, a single band of binding proteins with a molecular weight of 125 kDa being evident under non-reducing conditions. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that the TRTC-G1-C-A4 cells contained IGF-I receptor mRNA with a sequence corresponding to that determined from rat uterus. These results demonstrate that the IGF-I receptor can be expressed in a thyroid carcinoma with an important contribution to cell growth.

Recent advances in cytometry, cytogenetics and molecular genetics of thyroid tumours and tumour-like lesions

In this review we summarize the most recent advances of flow and image cytometry, cytogenetics and molecular genetics of tumours and tumour-like lesions of the thyroid, especially focusing on the putative relationship between nodular goitres and adenomas, the differential diagnosis of benign and malignant neoplasms and the pathogenesis and prognosis of carcinomas. Data obtained by in situ hybridization and immunohistochemical detection of proliferative markers, metal binding proteins and oncogenes, anti-oncogenes, growth factors and growth factor receptors are also used whenever appropriate.

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 Kd 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.