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

Circulating endogenous sex steroids and risk of differentiated thyroid carcinoma in men and women

Thyroid cancer (TC) is substantially more common in women than in men, pointing to a possible role of sex steroid hormones. We investigated the association between circulating sex steroid hormones, sex hormone binding globulin (SHBG) and the risk of differentiated TC in men and women within the European Prospective Investigation into Cancer and nutrition (EPIC) cohort. During follow-up, we identified 333 first primary incident cases of differentiated TC (152 in pre/peri-menopausal women, 111 in post-menopausal women, and 70 in men) and 706 cancer-free controls. Women taking exogenous hormones at blood donation were excluded. Plasma concentrations of testosterone, androstenedione, dehydroepiandrosterone, estradiol, estrone and progesterone (in pre-menopausal women only) were performed using liquid chromatography/mass spectrometry method. SHBG concentrations were measured by immunoassay. Odds ratios (ORs) were estimated using conditional logistic regression models adjusted for possible confounders. No significant associations were observed in men and postmenopausal women, while a borderline significant increase in differentiated TC risk was observed with increasing testosterone (adjusted OR T3 vs T1: 1.68, 95% CI: 0.96-2.92, ptrend = .06) and androstenedione concentrations in pre/perimenopausal women (adjusted OR T3 vs T1: 1.78, 95% CI: 0.96-3.30, ptrend = .06, respectively). A borderline decrease in risk was observed for the highest progesterone/estradiol ratio (adjusted OR T3 vs T1: 0.54, 95% CI: 0.28-1.05, ptrend = .07). Overall, our results do not support a major role of circulating sex steroids in the etiology of differentiated TC in post-menopausal women and men but may suggest an involvement of altered sex steroid production in pre-menopausal women.

Enhancing clinical decision-making: A novel nomogram for stratifying cancer-specific survival in middle-aged individuals with follicular thyroid carcinoma utilizing SEER data

Background

Thyroid cancer (TC) is the most common malignant tumor in the endocrine system, is also one of the head and neck tumor. Follicular Thyroid Carcinoma (FTC) plays an important role in the pathological classification of thyroid cancer. This study aimed to develop an innovative predictive tool, a nomogram, for predicting cancer specific survival (CSS) in middle-aged FTC patients.

Methods

We collected patient data from the Surveillance, Epidemiology, and End Results (SEER) database. The data from patients between 2004 and 2015 were used as the training set, and the data from patients between 2016 and 2018 were used as the validation set. To identify independent risk factors affecting patient survival, univariate and multivariate Cox regression analyses were performed. Based on this, we developed a nomogram model aimed at predicting CSS in middle-aged patients with FTC. The consistency index (C-index), the area under the receiver operating characteristic (ROC) curve (AUC), and the calibration curve were used to evaluate the accuracy and confidence of the model.

Results

A total of 2470 patients were enrolled in this study, in which patients from 2004 to 2015 were randomly assigned to the training cohort (N = 1437) and validation cohort (N = 598), and patients from 2016 to 2018 were assigned to the external validation cohort (N = 435) in terms of time. Univariate and multivariate Cox regression analysis showed that marriage, histological grade and TNM stage were independent risk factors for survival. The C-index for the training cohort was 0.866 (95 % CI: 0.805-0.927), for the validation cohort it was 0.944 (95 % CI: 0.903-0.985), and for the external validation cohort, it reached 0.999 (95 % CI: 0.997-1.001). Calibration curves and AUC suggest that the model has good accuracy.

Conclusions

We developed an innovative nomogram to predict CSS in middle-aged patients with FTC. Our model after a rigorous internal validation and external validation process, based on the time proved that the high level of accuracy and reliability. This tool helps healthcare professionals and patients make informed clinical decisions.

Spatiotemporal distribution of mediastinal neoplasms: A comprehensive multi-center study

OBJECTIVES

Mediastinal neoplasms are typical but uncommon thoracic diseases with increasing incidence and unfavorable prognoses. A comprehensive understanding of their spatiotemporal distribution is essential for accurate diagnosis and timely treatment. However, previous studies are limited in scale and data coverage. Therefore, this study aims to elucidate the distribution of mediastinal lesions, offering valuable insights into this disease.

MATERIALS AND METHODS

This multi-center, hospital-based observational study included 20 nationwide institutions. A retrospective search of electronic medical records from January 1st, 2009, to December 31st, 2020, was conducted, collecting sociodemographic data, computed tomography images, and pathologic diagnoses. Analysis focused on age, sex, time, location, and geographical region. Comparative assessments were made with global data from a multi-center database.

RESULTS

Among 7,765 cases, thymomas (30.7%), benign mediastinal cysts (23.4%), and neurogenic tumors (10.0%) were predominant. Distribution varied across mediastinal compartments, with thymomas (39.6%), benign cysts (28.1%), and neurogenic tumors (51.9%) most prevalent in the prevascular, visceral, and paravertebral mediastinum, respectively. Age-specific variations were notable, with germ cell tumors prominent in patients under 18 and aged 18-29, while thymomas were more common in patients over 30. The composition of mediastinal lesions across different regions of China remained relatively consistent, but it differs from that of the global population.

CONCLUSION

This study revealed significant heterogeneity in the spatiotemporal distribution of mediastinal neoplasms. These findings provide useful demographic data when considering the differential diagnosis of mediastinal lesions, and would be beneficial for tailoring disease prevention and control strategies.

Androgen Receptor Activation Induces Senescence in Thyroid Cancer Cells

Thyroid cancer (TC) is the most common endocrine malignancy, with an approximately three-fold higher incidence in women. TCGA data indicate that androgen receptor (AR) RNA is significantly downregulated in PTC. In this study, AR-expressing 8505C (anaplastic TC) (84E7) and K1 (papillary TC) cells experienced an 80% decrease in proliferation over 6 days of exposure to physiological levels of 5α-dihydrotestosterone (DHT). In 84E7, continuous AR activation resulted in G1 growth arrest, accompanied by a flattened, vacuolized cell morphology, with enlargement of the cell and the nuclear area, which is indicative of senescence; this was substantiated by an increase in senescence-associated β-galactosidase activity, total RNA and protein content, and reactive oxygen species. Additionally, the expression of tumor suppressor proteins p16, p21, and p27 was significantly increased. A non-inflammatory senescence-associated secretory profile was induced, significantly decreasing inflammatory cytokines and chemokines such as IL-6, IL-8, TNF, RANTES, and MCP-1; this is consistent with the lower incidence of thyroid inflammation and cancer in men. Migration increased six-fold, which is consistent with the clinical observation of increased lymph node metastasis in men. Proteolytic invasion potential was not significantly altered, which is consistent with unchanged MMP/TIMP expression. Our studies provide evidence that the induction of senescence is a novel function of AR activation in thyroid cancer cells, and may underlie the protective role of AR activation in the decreased incidence of TC in men.

Current status and temporal trend of disease burden of thyroid cancer in China from 1990 to 2019

OBJECTIVE

Thyroid cancer has been an increasingly high-profile public health issue. Comprehensive assessment for its disease burden seems particularly important for understanding health priorities and hinting high-risk populations.

METHODS

We estimated the age-sex-specific thyroid cancer burden and its temporal trend in China from 1990 to 2019 by following the general methods from the global burden of disease (GBDs) 2019 Study. And Joinpoint regression model, the Cox-Stuart trend test, and Cochran-Armitage test were applied for the analysis of temporal and age trend. The Mantel-Haenszel statistical method was used to compare the gender difference.

RESULTS

From 1990 to 2019, the age-standardized incidence rate of thyroid cancer in China has almost doubled to 2.05 per 100,000. Although the mortality rate and DALY rate kept leveling off, they presented a downtrend among females, while an upward trend in males. While the average annual percentage changes of those metrics all became deline since 2010 than the previous years. With age advancing, the rates of incidence, mortality, and DALYs for both sexes all presented linear fashion increases, which was particularly typical among males.

CONCLUSION

Given the serious trend and gender-age heterogeneity of Chinese thyroid cancer burden, male gender and advanced age may be related to poor prognosis of thyroid cancer, and strengthening primary prevention and exploring the underlying risk factors should be among the top priorities.

Sex differences in drug effects and/or toxicity in oncology

The prevalence, incidence, and severity of a wide variety of diseases and ailments are significantly influenced by the significant disparities that occur between the sexes. The way that men and women react to pharmacological treatment also varies. Therefore, it is crucial to comprehend these reactions in order to conduct risk assessment correctly and to develop safe and efficient therapies. Even from that limited vantage point, the manner and timing of our drug usage might have unintended and unanticipated consequences. There are sex-specific differences in the incidence and mortality of certain malignancies. One of the most important discoveries in cancer epidemiology is the gender inequalities. Cancer incidence differences between the sexes are thought to be regulated at the genetic and molecular levels and by sex hormones like oestrogen. Differences based on sex and gender are among the least investigated factors impacting cancer susceptibility, progression, survival, and therapy response despite their established importance in clinical care. The molecular mechanisms underlying sex differences in particular are poorly known, hence the majority of precision medicine approaches employ mutational or other genetic data to assign therapy without taking into account how the patient's sex may affect therapeutic efficacy. In patients receiving chemotherapy, there are definite gender-dependent disparities in response rates and the likelihood of side effects. This review explores the influence of sex as a biological variable in drug effects or toxicity in oncology.

Sex dimorphism in the tumor microenvironment - From bench to bedside and back

Cancer represents a significant cause of death and suffering in both the developed and developing countries. Key underlying issues in the mortality of cancer are delayed diagnosis and resistance to treatments. However, improvements in biomarkers represent one important step that can be taken for alleviating the suffering caused by malignancy. Precision-based medicine is promising for revolutionizing diagnostic and treatment strategies for cancer patients worldwide. Contemporary methods, including various omics and systems biology approaches, as well as advanced digital imaging and artificial intelligence, allow more accurate assessment of tumor characteristics at the patient level. As a result, treatment strategies can be specifically tailored and adapted for individual and/or groups of patients that carry certain tumor characteristics. This includes immunotherapy, which is based on characterization of the immunosuppressive tumor microenvironment (TME) and, more specifically, the presence and activity of immune cell subsets. Unfortunately, while it is increasingly clear that gender strongly affects immune regulation and response, there is a knowledge gap concerning differences in sex-specific immune responses and how these contribute to the immunosuppressive TME and the response to immunotherapy. In fact, sex dimorphism is poorly understood in cancer progression and is typically ignored in current clinical practice. In this review, we aim to survey the available literature and highlight the existing knowledge gap in order to encourage further studies that would contribute to understanding both gender-biased immunosuppression in the TME and the driver of tumor progression towards invasive and metastatic disease. The review highlights the need to include sex optimized/genderized medicine as a new concept in future medicine cancer diagnostics and treatments.

Uterine fibroids increase the risk of thyroid goiter and thyroid nodules

Uterine fibroid and benign thyroid disease are both common diseases in women. This study aimed to evaluate whether these diseases are related. We established the uterine fibroid group according to diagnosis and surgery codes using the Korea National Health Insurance data from 2009 to 2020. All women from 20 to 50 years old who underwent uterine myomectomy from 2009 to 2020 were identified. We selected the control group by performing a 1:1 propensity score matching on age at 5-year intervals, socioeconomic status (SES), region, Charlson comorbidity index (CCI), menopause, and year among women who visited a medical institution for a health check-up. Thyroid disease cases were selected using the thyroid disease diagnosis code and thyroid-associated laboratory tests. A total of 181,419 patients were included in the uterine fibroid and control groups. The median age of each group was 40 (range, 35 ~ 44) and 40 (range, 35 ~ 45) years old, respectively. Benign thyroid disease affected 1162 (0.6%) in the uterine fibroid group and 1137 (0.6%) in the control group. Among the benign thyroid diseases, hypothyroidism was the most common in both groups, followed by a nontoxic single thyroid nodule. The uterine fibroid group had a higher risk of thyroid goiter (hazard ratio (HR) 1.169, 95% confidence interval (CI) 1.022–1.338), nontoxic single thyroid nodule (HR 1.268, 95% CI 1.182–1.361), and total thyroid disease (HR 1.078, 95% CI 1.036–1.121) in stratified Cox regression analysis adjusted for age, SES, region, CCI, parity, menopause, hypertension, diabetes, dyslipidemia, systemic lupus erythematosus, irritable bowel syndrome, Crohn’s disease, and endometriosis than the control group. The results suggest that women with uterine fibroids have an increased risk of thyroid goiters and thyroid nodules. Although the mechanism is not well known, estrogen and iodide might be a link between uterine fibroids and thyroid goiters and nodules. Future studies that prospectively follow women with uterine fibroids across a lifetime are needed.

Decreased Expression of Estrogen Receptors Is Associated with Tumorigenesis in Papillary Thyroid Carcinoma

Papillary thyroid carcinomas (PTC), which is derived from thyroid follicular cells, is the most commonly differentiated thyroid cancer with sex disparity. However, the role of estrogen receptors (ERs) in the pathogenesis of PTC remains unclear. The present study aimed to determine the association of ER mRNA expression levels with clinicopathologic features in PTC. To that aim, the mRNA levels of ESR1 (ERα66), ESR1 (ERα36), ESR2, and G-protein-coupled estrogen receptor 1 (GPER1) in snap-frozen tissue samples from PTCs and adjacent normal thyroid tissues were determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the correlation between ER mRNA expression levels and clinicopathologic features was analyzed. The expression of ERα66, ERα36, ERβ, and GPER1 was lower in PTC specimens than in adjacent normal thyroid tissues. Moreover, low GPER1 expression was associated with extrathyroidal extension. There was no obvious difference in expression of ERs between PTC specimens from male and female patients. In conclusion, our findings highlight the importance of ERs in PTC tumorigenesis.

Pregnancy has no significant impact on the prognosis of differentiated thyroid cancer

OBJECTIVE

To evaluate the impact of pregnancy on differentiated thyroid carcinomas (DTC) behavior.

METHODS

Retrospective study of patients diagnosed with DTC before or during pregnancy and treated with standard therapy. In women diagnosed with DTC before pregnancy, we evaluated the occurrence of progression according to categories of response to therapy based on imaging and non-stimulated thyroglobulin (TG) levels.

RESULTS

Of 96 analyzed patients, 76 became pregnant after DTC treatment and 20 were diagnosed with DTC during pregnancy. Among women who became pregnant after a DTC diagnosis, no difference was observed regarding response to therapy before and after pregnancy. Disease progression after pregnancy was documented in six of these patients, while seven of them presented progression before pregnancy but were only treated after delivery. Patients with DTC diagnosed during pregnancy had a higher rate of distant metastases at diagnosis (30%) compared with the patients who became pregnant after DTC diagnosis (9.2%, p = 0.01).

CONCLUSION

Pregnancy had no impact on the natural course of DTC. Disease progression after pregnancy was limited and probably related to more aggressive disease and higher risk stratification at diagnosis. Still, mild disease progression may have occurred asymptomatically in some patients.

Oestrogen receptor alpha in papillary thyroid carcinoma: association with clinical features and BRAFV600E mutation

BACKGROUND

Papillary thyroid cancer cells can express oestrogen receptor alpha, which is encoded by the ESR1 gene and may bind to oestrogen to induce the occurrence and development of papillary thyroid cancer. The BRAFV600E mutation is also an important biomarker for the occurrence and progression of papillary thyroid cancer. However, the association between the BRAFV600E mutation and oestrogen receptor alpha expression has not been identified. This study aims to investigate the association between ESR1 expression and the BRAFV600E mutation and its clinical significance.

METHODS

Oestrogen receptor alpha and BRAFV600E proteins were detected by immunohistochemical staining of formalin-fixed paraffin-embedded thyroid tissues from 1105 patients with papillary thyroid cancer at our institution. Messenger RNA expression counts of ESR1 and clinicopathologic information were obtained from The Cancer Genome Atlas database.

RESULTS

Oestrogen receptor alpha protein expression was significantly associated with BRAFV600E protein. The positive rate of oestrogen receptor alpha protein in papillary thyroid cancer patients was significantly higher in males, younger patients and patients with the multifocal type. In papillary thyroid cancer patients with positive BRAFV600E protein, oestrogen receptor alpha expression was significantly correlated with central lymph node metastasis. Data from the The Cancer Genome Atlas database also suggested that the ESR1 messenger RNA level was associated with the BRAFV600E mutation. Furthermore, classification analysis performed according to a tree-based classification method demonstrated that higher ESR1 messenger RNA expression indicated poorer overall survival in papillary thyroid cancer patients with the BRAFV600E mutation.

CONCLUSIONS

The percentage of BRAFV600E mutations is increased in patients with higher ESR1 messenger RNA levels, and the BRAFV600E protein might be co-expressed with oestrogen receptor alpha, which could be an indicator of cervical lymph node metastasis and poor overall survival in patients with papillary thyroid cancer.

Trends in incidence and histological pattern of thyroid cancer in Ho Chi Minh City, Vietnam (1996-2015): a population-based study

BACKGROUND

The burden and trend of thyroid cancer in Vietnam have not been well documented. This study aimed to investigate the trends in incidence and histological pattern of thyroid cancer in Ho Chi Minh City from 1996 to 2015.

METHODS

A population-based study retrieved data from the Ho Chi Minh City Cancer Registry during 1996-2015. Trends in the incidence of thyroid cancer were investigated based on age, gender, and histology for each 5-year period. Annual percentage change (APC) in incidence rates was estimated using Joinpoint regression analysis.

RESULTS

In the study period, there were 5953 thyroid cancer cases (men-to-women ratio 1:4.5) newly diagnosed in Ho Chi Minh City with the mean age of 42.9 years (±14.9 years). The age-standardized incidence rate of thyroid cancer increased from 2.4 per 100,000 during 1996-2000 (95% confidence interval [95% CI]: 2.2-2.6) to 7.5 per 100,000 during 2011-2015 (95% CI: 7.3-7.9), corresponded to an overall APC of 8.7 (95% CI 7.6-9.9). The APC in men and women was 6.2 (95% CI: 4.2-8.2) and 9.2 (95% CI: 8.0-10.4), respectively. The incidence rate in the < 45 years age group was the highest diagnosed overall and increased significantly in both men (APC 11.0) and women (APC 10.1). Both genders shared similar distribution of subtype incidences, with papillary thyroid cancer constituted the most diagnosed (73.3% in men and 85.2% in women). The papillary thyroid cancer observed a markedly increase overall (APC of 10.7 (95% CI 9.3-12.0)).

CONCLUSIONS

There were appreciable increases in the age-standardized incidence rate of thyroid cancer in both genders, mainly contributed by the papillary subtype. The age of patients at diagnosis decreased gradually. The widespread utilization of advanced diagnostic techniques and healthcare accessibility improvement might play a potential role in these trends. Further investigations are needed to comprehend the risk factors and trends fully.

Estrogen Receptor Beta: The Promising Biomarker and Potential Target in Metastases

The discovery of the Estrogen Receptor Beta (ERβ) in 1996 opened new perspectives in the diagnostics and therapy of different types of cancer. Here, we present a review of the present research knowledge about its role in endocrine-related cancers: breast, prostate, and thyroid, and colorectal cancers. We also discuss the reasons for the controversy of its role in carcinogenesis and why it is still not in use as a biomarker in clinical practice. Given that the diagnostics and therapy would benefit from the introduction of new biomarkers, we suggest ways to overcome the contradictions in elucidating the role of ERβ.

Association Between Aggressive Clinicopathologic Features of Papillary Thyroid Carcinoma and Body Mass Index: A Systematic Review and Meta-Analysis

BACKGROUND

The association between adiposity and papillary thyroid carcinoma (PTC) has been reported in several studies, but its association with aggressive clinicopathologic features is not well-recognized. Our aim is to systematically review the literature to identify whether adiposity, expressed through Body Mass Index (BMI), is related to aggressive clinicopathologic features such as tumor-node-metastasis (TNM) stage, extrathyroidal extension (ETE), lymph node (LN) metastasis and multifocality in patients with PTC.

METHODS

A systematic search for articles was performed using the PubMed, EBSCO, and Cochrane Library for all articles published in English until December 2020. Specific keywords such as "papillary thyroid carcinoma", "Body Mass Index", "clinicopathologic features" were used in the search strategy. Two independent reviewers screened all retrieved articles based on predefined inclusion and exclusion criteria. Meta-analysis was performed in the studies that reported crude and adjusted odds ratios (OR). The methodological quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 11 retrospective cohort studies involving 26,196 participants included. Our findings showed that elevated BMI was significantly associated with ETE in both overweight (OR 1.26, 95% CI: 1.09-1.44) and obesity group (OR 1.45, 95% CI:1.26-1.64). Elevated BMI was also significantly associated with multifocality in overweight patients (OR 1.17, 95% CI:1.10-1.24) and obese patients (OR 1.45, 95% CI:1.29-1.62). Also, obesity was significantly associated with increased tumor size (OR 1.77, 95% CI:1.52-2.03) and with LN metastasis (OR 1.28, 95% CI: 1.12-1.44), whereas being overweight was significantly associated with advanced TNM stage (OR 1.55, 95% CI:1.27-1.83).

CONCLUSION

Our results provide strong evidence for the association between higher BMI and ETE, multifocality, and tumor size. Further studies with a larger number of participants are required to elucidate further the association of increased BMI with advanced TNM stage and LN metastasis.

Papillary Thyroid Carcinoma in Children: Clinicopathological Profile and Outcomes of Management

BACKGROUND

We aim to analyze the clinicopathological profile and outcomes of management for children with papillary thyroid carcinoma (PTC).

METHODS

Relevant clinical data of children ≤ 18 years of age managed for PTC between January 2006 and July 2018 as well as details of their follow-up till December 2019 were retrospectively collected and analyzed.

RESULTS

There were 82 children with PTC that were managed during the study period. At presentation, 39 (47.6%) had cervical lymphadenopathy, while 9 (11%) had systemic metastasis. Majority of patients 39 (47.6%) underwent total thyroidectomy with a selective neck dissection, while total thyroidectomy alone was performed in 26 (31.7%). Following surgery, hypocalcemia was seen in 39 (47.6%): 28 (34.1%) were temporary, while 11 (13.4%) were permanent. Twenty-eight (34%) developed persistent disease after surgery and ¹³¹I therapy. Significant risk factors for persistence and metastatic disease were metastatic cervical lymph node at presentation (p = 0.002) and tumor size (p = 0.014), respectively. The mean duration of follow-up was 60.3 (range 12-150) months with a mean overall disease-free survival of 60 months (95% CI 57.11, 77.95).

CONCLUSION

Children with papillary thyroid cancers present with aggressive disease, 47.6% with cervical nodal metastasis and 11% with distant metastasis in this cohort. The rate of post-thyroidectomy hypocalcemia in this study is substantial, and efforts to reduce it are actively being pursued. The presence of metastatic cervical lymph node at presentation (p = 0.002) and tumor size (p = 0.014) were the only significant risk factors for persistent and metastatic disease, respectively, in this study.

Glucagon-like peptide-1 analogues and thyroid cancer: An analysis of cases reported in the European pharmacovigilance database

WHAT IS KNOWN AND OBJECTIVE

The use of glucagon-like peptide-1 (GLP-1) analogues has been linked to the risk of thyroid cancer. Spontaneous reports can provide information about rare adverse events occurring after the time of marketing. Our objective was to detect, from the European pharmacovigilance database (EudraVigilance), a signal of thyroid cancer during GLP-1 analogues treatment in patients with diabetes.

METHODS

Herein, we analysed all reports of thyroid cancer reported with GLP-1 analogues in EudraVigilance database from their first marketing authorization till 30 January 2020. A case/non-case method was used to assess the association between thyroid cancer and GLP-1 analogues, calculating proportional reporting ratios (PRRs) and their 95% confidence interval (CI) as a measure of disproportionality. The cases were identified with Medical Dictionary for Regulatory Activities (MedDRA) version 22.1.

RESULTS AND DISCUSSION

There were 11 243 cases of thyroid cancer and related preferred terms (PTs) in the 6 665 794 reports recorded in EudraVigilance during the study period. GLP-1 analogues were involved in 236 cases. Exenatide, liraglutide and dulaglutide met the criteria to generate a safety signal, suggesting that thyroid cancer is reported relatively more frequently in association with these drugs than with other medicinal products. The association was strongest for liraglutide followed by exenatide with PRR of 27.5 (95% CI, 22.7-33.3) and 22.5 (95% CI, 17.9-28.3), respectively. Disproportionality was also observed for GLP-1 analogues and individual identified preferred term, that is thyroid cancer (N = 111), medullary thyroid cancer (N = 64) and thyroid neoplasm (N = 46) with PRR of 14.4 (95% CI, 11.8-17.4), 221.5 (95% CI, 155.7-315.1) and 35.5 (95% CI, 25.9-48.5), respectively.

WHAT IS NEW AND CONCLUSIONS

Our findings showed disproportionality for thyroid cancer, medullary thyroid cancer and thyroid neoplasm in patients treated with GLP-1 analogues. We have found evidence from spontaneous reports that GLP-1 analogues are associated with thyroid cancer in patients with diabetes.

Histopathological and Immunohistochemical Characteristics of Thyroid Carcinoma in the Dog

Thyroid carcinomas are a common form of endocrine neoplasia in dogs. In the present study, we combined histopathology with immunohistochemistry (IHC) to search for the presence of oestrogen receptor alpha (ORα), Cox-2 and Ki67 in canine thyroid carcinomas. Forty-eight thyroid carcinomas were diagnosed throughout the study period. Thyroglobulin and calcitonin IHC distinguished between thyroid tumours with a follicular and medullary (C-cell) origin, respectively. IHC-based diagnosis showed that 42 (87.50%) of the cases were follicular cell carcinoma. In these cases, the follicular-compact pattern was the most frequent (n = 20/42; 47.62%) and six cases (12.5%) were medullary cell (C-cell) carcinomas. Both medullary (C-cell) and follicular carcinomas expressed Ki67 and Cox-2. No differences were observed between medullary and follicular carcinomas with respect to expression of Ki67 (P = 0.34) and Cox-2 (P = 0.9523) markers. A total of 4.17% (n = 2/48) of thyroid carcinomas showed positive nuclear labelling for ORα, suggesting that oestrogen does not directly participate in the pathogenesis of canine thyroid neoplasia.

Papillary Thyroid Cancer-Promoting Activities of Combined Oral Contraceptive Components

Background:

Thyroid cancer is more common in women at reproductive age, suggesting the relationship between its high-incidence and therapeutic use of hormonal medications, such as oral contraceptives (OCPs). The aim of this study was to identify the effect of low-dose combined OCP (LD-COC) on proliferation, apoptosis, and migration of human papillary thyroid cancer (PTC) BCPAP cell line.

Materials and Methods:

BCPAP cells were cultured and treated with the combination of 90nM levonorgestrel (LNG) and 20nM ethinylestradiol (EE) for 48 hours. Afterward, using 3-(4, 5-dimethylthiazol-2-yl) -2, 5-diphenyltetrazolium bromide (MTT) assay, the proliferation of the cells was measured. Apoptosis was determined by using a Caspase-3 ELISA kit. Migratory properties of combined LNG and EE were studied through wound scratch assay. The expression levels of pro-apoptotic factor BAX, anti-apoptotic factor Bcl2, and proliferation marker Ki67 were analyzed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blotting.

Results:

Upon treatment with the combination of LNG and EE, proliferation and migration of BCPAP cells were significantly enhanced. However, LNG and EE remarkably inhibited apoptosis of these cells. Furthermore, treating PTC cells with combined LNG and EE caused a marked increase in the expression of Bcl2 and Ki67 and a considerable decrease in BAX levels (P˂0.05).

Conclusion:

Our data linked the use of COCs and the progression and aggressiveness of PTC, suggesting the role of these hormonal compounds as promoting factors for PTC tumors. Despite these observations, further investigations will be required to fully establish the pathogenic impact of these medications on PTC.

Aberrant Expression of Androgen Receptor Associated with High Cancer Risk and Extrathyroidal Extension in Papillary Thyroid Carcinoma

Male gender is a risk factor for mortality in patients with papillary thyroid carcinoma (PTC). This study investigated the impact of androgen receptor (AR) gene expression on the clinical features and progression of PTC. The levels of AR mRNA and protein in frozen, formalin-fixed, paraffin-embedded tissue samples from PTC and adjacent normal thyroid tissue were assessed by quantitative real-time polymerase chain reaction and immunohistochemical staining, respectively, and the relationships between AR expression and clinical features were analyzed. The thyroid cancer cell lines, BCPAP and TPC-1, were used to evaluate the effects of AR on the regulation of cell migration, and key epithelial-mesenchymal transition (EMT) markers. AR mRNA expression was significantly higher in normal thyroid tissue from men than women. The sex difference in AR mRNA expression diminished during PTC tumorigenesis, as AR mRNA expression levels were lower in PTC than normal thyroid tissues from both men and women. AR mRNA expression was significantly decreased in PTC patients with higher risk and in those with extrathyroidal extension. Overexpression of AR in BCPAP cells decreased cell migration and repressed the EMT process by down-regulating mRNA expression of N-cadherin, Snail1, Snail2, Vimentin, and TWIST1 and up-regulating E-cadherin gene expression. These results suggest that suppression of the androgen-AR axis may lead to aggressive tumor behavior in patients with PTC.

Menstrual and reproductive factors in the risk of thyroid cancer in Japanese women: the Japan Public Health Center-Based Prospective Study

The aim of this study was to evaluate the associations between menstrual and reproductive factors and thyroid cancer risk among Japanese women. A total 54 776 women aged 40-69 years completed a self-administered questionnaire, which included menstrual and reproductive history. During 1990-2012, 187 newly diagnosed cases of thyroid cancer were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) for menstrual and reproductive factors and incidence of thyroid cancer were estimated using Cox proportional hazards regression. Postmenopausal women who had natural menopause were at reduced risk of thyroid cancer than premenopausal women in the age-area-adjusted model (HR: 0.62 per 1 year increase, 95% CI: 0.39-0.99), but this association was slightly attenuated and no longer statistically significant in the multivariable-adjusted model. On analysis by menopausal status, an inverse association between age at menarche and risk of thyroid cancer was observed for premenopausal women (HR: 0.83 per 1 year increase, 95% CI: 0.70-0.98, P trend=0.03), but not for postmenopausal women. The risk of thyroid cancer increased with surgical menopause compared with natural menopause (HR: 2.34, 95% CI: 1.43-3.84). Although increasing age at menopause and duration of fertility were associated with an increased risk of thyroid cancer, this association was not observed among postmenopausal women. This study confirmed that early age at menarche for premenopausal women and surgical menopause and late age at natural menopause for postmenopausal women were associated with the development of thyroid cancer. Our results support the hypothesis that exposure to estrogens increases the risk of thyroid cancer.

Are pregnancy, parity, menstruation and breastfeeding risk factors for thyroid cancer? Results from the Korea National Health and Nutrition Examination Survey, 2010-2015

CONTEXT

It is unclear whether reproductive factors such as pregnancy, parity, menstruation, and breastfeeding are risk factors for thyroid cancer. The aim of this study was to evaluate the association of reproductive factors with thyroid cancer risk.

DESIGN/SETTING

Large-scale nation-wide cross-sectional data were analysed from representative samples from the Korea National Health and Nutrition Examination Survey V-VI (2010-2015).

RESULTS

In this study, 38 086 people over the age of 18 years were enrolled, of which 241 had a diagnosis of thyroid cancer. Of 21 543 female subjects, 210 had thyroid cancer. In logistic regression analysis, pregnancy, parity and number of reproductive years (period between menarche and menopause, excluding breastfeeding period) were significantly associated with thyroid cancer after adjusting for age, body mass index and smoking. However, the number of pregnancies did not show a linear relationship with thyroid cancer. Among breastfeeding women, total duration of breastfeeding and number of babies breastfed significantly decreased the risk for thyroid cancer.

CONCLUSION

Our findings suggest that reproductive factors can be associated with the development of thyroid cancer. A large prospective cohort study is needed to clarify the causality.

Impact of Gender and Age on the Prognosis of Differentiated Thyroid Carcinoma: a Retrospective Analysis Based on SEER

The incidence of thyroid cancer in females is significantly higher than that in males; however, females are more likely to have more favorable outcomes. We aimed to determine the characteristics of differentiated thyroid carcinoma (DTC) subtypes in males and females, and to compare their clinical behavior and survival. A total of 68,337 cases were recruited from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program. The disease-specific survival (DSS) of follicular variant papillary thyroid carcinoma (FVPTC) and follicular thyroid carcinoma (FTC) were similar to that of classical variant papillary thyroid carcinoma (CPTC) in male patients (FVPTC vs. CPTC, adjusted hazard ratio (aHR) = 0.947, P = 0.776; FTC vs. CPTC, aHR = 1.512, P = 0.104). In premenopausal female (< 55 years old), FVPTC had better DSS than CPTC (aHR = 0.321, P = 0.038) while FTC had worse DSS than CPTC (aHR = 3.272, P = 0.013); in postmenopausal female, FTC had poorer prognosis than CPTC (aHR = 2.145, P = 0.002), no statistical difference was found between CPTC and FVPTC (aHR = 0.724, P = 0.087). For patients younger than 55 years, women had significantly better DSS compared with men with CPTC (aHR = 0.376, P < 0.001) and FVPTC (aHR = 0.102, P < 0.001). However, no difference was observed in patients older than 55 years. Interestingly, outcomes of FTC were not affected by gender in patients of all ages. These results suggested that different clinical behaviors and outcomes of DTC subtypes should be considered in patients with different genders.

Review of the possible association between thyroid and breast carcinoma

Background

Thyroid and breast cancer are two of the malignant diseases with highest incidence in females. Based on clinical experience, breast and thyroid cancer often occur metachronously or synchronously. Therefore, thyroid and breast cancer might share some common etiological factors. The relationship between these diseases has attracted substantial attention, and because these two glands are both regulated by the hypothalamic-pituitary axis, such a relationship is not surprising. A study of this relationship will be useful for obtaining a better understanding of the mechanism by which these two malignancies co-occur.

Main body

This study reviewed the progress in research on the roles of iodine intake, folate metabolism, obesity, gonadal hormones, and thyroid hormone in thyroid and breast cancer. These studies evaluating the etiological roles of these factors in linking breast and thyroid cancer might also improve our understanding and identify new therapeutic approaches, such as sodium/iodide symporter-mediated radioiodine therapy and thyroid-stimulating hormone receptor antagonists, for breast cancer. In addition, some specific treatments for each cancer, such as radiotherapy for breast cancer or radioactive iodine therapy for thyroid cancer, might be risk factors for secondary malignances, including breast and thyroid cancer.

Conclusions

Studies of the precise relationship between the co-occurrence of breast and thyroid cancer will certainly improve our understanding of the biological behaviors of these two malignancies and direct evidence-based clinical practice.

Sex Differences in Cancer: Epidemiology, Genetics and Therapy

The incidence and mortality of various cancers are associated with sex-specific disparities. Sex differences in cancer epidemiology are one of the most significant findings. Men are more prone to die from cancer, particularly hematological malignancies. Sex difference in cancer incidence is attributed to regulation at the genetic/molecular level and sex hormones such as estrogen. At the genetic/molecular level, gene polymorphism and altered enzymes involving drug metabolism generate differences in cancer incidence between men and women. Sex hormones modulate gene expression in various cancers. Genetic or hormonal differences between men and women determine the effect of chemotherapy. Until today, animal studies and clinical trials investigating chemotherapy showed sex imbalance. Chemotherapy has been used without consideration of sex differences, resulting in disparity of efficacy and toxicity between sexes. Based on accumulating evidence supporting sex differences in chemotherapy, all clinical trials in cancer must incorporate sex differences for a better understanding of biological differences between men and women. In the present review, we summarized the sex differences in (1) incidence and mortality of cancer, (2) genetic and molecular basis of cancer, (3) sex hormones in cancer incidence, and (4) efficacy and toxicity of chemotherapy. This review provides useful information for sex-based chemotherapy and development of personalized therapeutic strategies against cancer.

Immunohistochemical expression of ER-α and PR in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer with multiple risk factors including exposure to ionising radiation. Oestrogens contribute to papillary carcinoma development by promoting cell proliferation and invasion of mutated epithelial follicular cells. The present study aimed to assess ER-α and PR expression in PTC and to correlate their expression with the clinicopathological parameters in this cancer. This study included 62 primary and six metastatic papillary thyroid carcinoma cases. Nineteen and 38.7% of primary PTC cases showed positive nuclear expression for ER and PR, respectively. Metastatic cases showed 66.7% positive ER expression and all were negative for PR. Oestrogen receptor expression showed significant higher positivity in metastatic compared to primary PTC (p = 0.02) and it was significantly associated with primary PTC associated with thyroiditis (p = .002). Progesterone receptor expression was significantly associated with old age in primary PTC (p = .003) and it showed significant coparallel expression with ER (p = .000). Oestrogen and progesterone receptors expressed in papillary thyroid carcinoma opening the door for further studies to verify if those patients could benefit from hormonal therapy. Oestrogen receptor seems to have a role in metastatic process of PTC as malignant cells express it in metastatic more than primary site. The presence of lymphocytes in the stroma may promote ER expression in adjacent PTC, necessitating further studies on PTC cases associated with Hashimoto thyroiditis to verify this assumed relationship.

Upregulation of the ESR1 Gene and ESR Ratio (ESR1/ESR2) is Associated with a Worse Prognosis in Papillary Thyroid Carcinoma: The Impact of the Estrogen Receptor α/β Expression on Clinical Outcomes in Papillary Thyroid Carcinoma Patients

BACKGROUND

A gender disparity exists with respect to the incidence of papillary thyroid cancer (PTC), suggesting that sex hormones such as estrogen play a role in PTC development and progression. In this study, we compared estrogen receptor gene expression patterns in PTCs to determine the clinical significance of estrogen gene expression in PTC.

METHODS

We analyzed ESR1 and ESR2 messenger RNA expression counts using data from The Cancer Genome Atlas (TCGA). To validate the results of TCGA analysis, we analyzed microarray data (GSE 54958) from the Gene Expression Omnibus.

RESULTS

ESR1 gene expression and ESR ratio (ESR1/ESR2) were significantly higher in PTC tissues than in paired normal thyroid tissues (mean 659.427 vs. 264.045 for ESR1, 92.017 vs. 19.064 for ESR ratio). Among female patients, ESR1 expression and ESR ratio were negatively correlated with increased age. ESR1 expression and ESR ratio were higher in patients with classic PTC, lymphovascular invasion, BRAF ^V600E mutation, and radioiodine therapy. Classification analysis demonstrated that higher ESR1 expression and a higher ESR ratio faced a worse overall survival (hazard ratio 6.348 for ESR1, 4.031 for ESR ratio). Validation microarray analysis demonstrated that ESR1 expression and ESR ratio were higher in tumor tissues, classic PTC, and BRAF ^V600E.

CONCLUSION

Higher ESR1 expression and a higher ESR ratio were associated with aggressive prognostic factors and worse overall survival in female PTC patients. Our results suggest that ESR1 and ESR ratio can be used as prognostic markers to predict female patient survival and have potential as a therapeutic target.

Estrogen and thyroid cancer is a stem affair: A preliminary study

Gender influences Papillary Thyroid Cancer (PTC) with an incidence of 3:1 when comparing women to men with different aggressiveness. This gender discrepancy suggests some role of sex hormones in favoring the malignant progression of thyroid tissue to cancer. Estrogens are known to promote Stem Cell self-renewal and, therefore, may be involved in tumor initiation. The goals of these studies are to investigate the underlying causes of gender differences in PTC by studying the specific role of estrogens on tumor cells and their involvement within the Cancer Stem Cell (CSC) compartment. Exposure to 1nmoll^-1 Estradiol for 24h promotes growth and maintenance of PTC Stem Cells, while inducing dose-dependent cellular proliferation and differentiation following Estradiol administration. Whereas mimicking a condition of hormonal imbalance led to an opposite phenotype compared to a continuous treatment. In vivo we find that Estradiol promotes motility and tumorigenicity of CSCs. Estradiol-treated mice inoculated with Thyroid Cancer Stem Cell-enriched cells developed larger tumor masses than control mice. Furthermore, Estradiol-pretreated Cancer Stem cells migrated to distant organs, while untreated cells remained circumscribed. We also find that the biological response elicited by estrogens on Papillary Thyroid Cancer in women differed from men in pathways mediated. This could explain the gender imbalance in tumor incidence and development and could be useful to develop gender specific treatment of (PTC).

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.

Up-regulation of Hsp27 by ERα/Sp1 facilitates proliferation and confers resistance to apoptosis in human papillary thyroid cancer cells

17β-estradiol (E2) has been suggested to play a role in the development and progression of papillary thyroid cancer. Heat shock protein 27 (Hsp27) is a member of the Hsp family that is responsible for cell survival under stressful conditions. Previous studies have shown that the 5'-promoter region of Hsp27 gene contains a specificity protein-1 (Spl) and estrogen response element half-site (ERE-half), which contributes to Hsp27 induction by E2 in breast cancer cells. However, it is unclear whether Hsp27 can be up-regulated by E2 and which estrogen receptor (ER) isoform and tethered transcription factor are involved in this regulation in papillary thyroid cancer cells. In the present study, we demonstrated that Hsp27 can be effectively up-regulated by E2 at mRNA and protein levels in human K1 and BCPAP papillary thyroid cancer cells which have more than two times higher level of ERα than that of ERβ. The up-regulation of Hsp27 by E2 is mediated by ERα/Sp1 and ERβ has repressive effect on this ERα/Sp1-mediated up-regulation of Hsp27. Moreover, we showed that the up-regulation of Hsp27 by ERα/Sp1 facilitates proliferation and confers resistance to apoptosis through interaction with procaspase-3. Targeting this pathway may be a potential strategy for therapy of papillary thyroid cancer.

Sexual dimorphism in cancer

The incidence of many types of cancer arising in organs with non-reproductive functions is significantly higher in male populations than in female populations, with associated differences in survival. Occupational and/or behavioural factors are well-known underlying determinants. However, cellular and molecular differences between the two sexes are also likely to be important. In this Opinion article, we focus on the complex interplay that sex hormones and sex chromosomes can have in intrinsic control of cancer-initiating cell populations, the tumour microenvironment and systemic determinants of cancer development, such as the immune system and metabolism. A better appreciation of these differences between the two sexes could be of substantial value for cancer prevention as well as treatment.

Parity and thyroid cancer risk: a meta-analysis of epidemiological studies

Although observational studies have assessed the relationship between parity and thyroid cancer risk, the findings are inconsistent. To quantitatively assess the association, we conducted a systematic review and meta-analysis. PubMed and Embase were searched up to January 2015. Prospective or case-control studies that evaluated the association between parity and thyroid cancer risk were included. We used the fixed-effects model to pool risk estimates. After literature search, 10 prospective studies, 12 case-control studies and 1 pooled analysis of 14 case-control studies including 8860 patients were identified. The studies had fair methodological quality. Pooled analysis suggested that there was a significant association between parity and risk of thyroid cancer (RR for parous versus nulliparous: 1.09, 95% CI 1.03-1.15; I2=33.4%). The positive association persisted in almost all strata of subgroup analyses based on study design, location, study quality, type of controls, and confounder adjustment, although in some strata statistical significance was not detected. By evaluating the number of parity, we identified that both parity number of 2 versus nulliparous and parity number of 3 versus nulliparous demonstrated significant positive associations (RR=1.11, 95% CI 1.01-1.22; I2=31.1% and RR=1.16, 95% CI 1.01-1.33; I2=19.6% respectively). The dose-response analysis suggested neither a non-linear nor linear relationship between the number of parity and thyroid cancer risk. In conclusion, this meta-analysis suggests a potential association between parity and risk of thyroid cancer in females. However, the lack of detection of a dose-response relationship suggests that further studies are needed to better understand the relationship.

Breastfeeding and thyroid cancer risk in women: A dose-response meta-analysis of epidemiological studies

BACKGROUND & AIMS

The association between breastfeeding and thyroid cancer risk is not consistent from epidemiological studies. To better clarify the association including assessing a potential dose-response relationship, we conducted a comprehensive meta-analysis.

METHODS

We searched PubMed (MEDLINE) up to November 2015 for prospective studies or case-control studies that evaluated the association between breastfeeding and risk of thyroid cancer. Effect estimates were pooled using a fixed-effects model.

RESULTS

Nine reports (2 prospective studies, 6 case-control studies and 1 pooled analysis of 14 case-control studies) involving 2423 cases and 350,081 non-cases were identified. After pooling relevant studies, there was a significant inverse association between ever breastfeeding and risk of thyroid cancer (RR = 0.91, 95% CI 0.83-0.99), with minor heterogeneity (I(2) = 10.1%). The dose-response analysis revealed a significant linear relationship between the duration of breastfeeding and risk of thyroid cancer. The summary RR for an increment of 1 month of breastfeeding with risk of thyroid cancer was 0.983 (95% CI 0.98-0.99). When focusing on cohort studies, a more prominent linear dose-response relationship was detected, with the combined RR for every increment of 1 month of breastfeeding to be 0.965 (95% CI 0.96-0.97).

CONCLUSIONS

This meta-analysis suggests that breastfeeding is potentially inversely associated with thyroid cancer risk. Also longer duration of breastfeeding may further decreases thyroid cancer risk. If validated in large-scale prospective studies, our findings may have implications for impacting women's decision in breastfeeding.

Testosterone and estradiol treatments differently affect pituitary-thyroid axis and liver deiodinase 1 activity in orchidectomized middle-aged rats

We previously reported that orchidectomy (Orx) of middle-aged rats (15-16-month-old; MA) slightly affected pituitary-thyroid axis, but decreased liver deiodinase (Dio) type 1 and pituitary Dio2 enzyme activities. At present, we examined the effects of subsequent testosterone-propionate treatment (5mg/kg; Orx+T), and compared the effects of testosterone with the effects of estradiol-dipropionate (0.06mg/kg; Orx+E) treatment. Hormones were subcutaneously administered, daily, for three weeks, while Orx and sham-operated (SO) controls received only the vehicle. The applied dose of T did not alter serum TSH, T4 and T3 concentrations in Orx- MA, though it increased TSH when administrated to Orx young adults (2.5-month-old; Orx-YA). However, pituitaries of Orx-MA+T rats had higher relative intensity of immunofluorescence (RIF) for TSHβ; in their thyroids we found increased volume and height of follicular epithelium, decreased volume of the colloid and higher RIF for T4-bound to thyroglobulin (Tg-T4). Liver Dio1 activity was increased. E-treatment did not affect serum hormone levels, pituitary RIF for TSHβ, or liver Dio1 activity in Orx-MA rats. Thyroids had decreased relative volume and height of follicular epithelium, increased relative volume of the colloid, decreased volume of sodium-iodide symporter-immunopositive epithelium and lower RIF for Tg-T4. Detected changes were statistically significant. In conclusion, androgenization enhanced pituitary TSHβ RIF, thyroid activation and liver Dio1 enzyme activity in Orx-MA, without elevating serum TSH as in Orx-YA rats. Estrogenization induced pituitary enlargement with no effect on pituitary TSHβ RIF, serum TSH or liver Dio1 activity. E also induced alterations in thyroid histology that indicate mild suppression of its functioning, and contributed to thyroid blood vessel enlargement in Orx-MA rats.

ER-alpha and ER-beta expression in differentiated thyroid cancer: relation with tumor phenotype across the TNM staging and peri-tumor inflammation

Thyroid cancer may express estrogen receptors (ERs) and various grades of peri-tumor inflammation. The aim of the study was to evaluate the expression of ERs in relation to the TNM stage and peri-tumor inflammatory infiltrate in differentiated thyroid cancers. 127 patients (109 females, 18 males) with differentiated thyroid cancer (T1 = 91, T2 = 18, T3 = 11, T4 = 7) were evaluated. In tumors and in the correspondent extra-tumor parenchyma, ERs expression was evaluated by immunohistochemistry. In 114 tumors and correspondent peri-tumor tissues, the presence of inflammatory infiltration was also recorded. ER-alpha expression was higher in clinical than in incidental tumors of the T1 subgroup (p = 0.037), and was associated with capsular invasion in T2 tumors (p < 0.0001). ER-beta expression was negatively associated with vascular invasion in T1 (p = 0.005) and T2 tumors (p = 0.015). No significant relationship between ERs expression and tumor phenotype emerged in T3 and T4 subgroups. Tumors without inflammatory cell infiltrate showed a higher expression of both ER-alpha (p = 0.035) and ER-beta (p = 0.026) than the ones with inflammatory infiltrate. The relationship between tumor phenotype and ERs expression did not vary in the presence or absence of peri-tumor inflammatory infiltration. ER-alpha positivity and ER-beta negativity are associated with a more aggressive phenotype in both T1 and T2 thyroid cancers, suggesting that tumor biology may be more relevant than tumor size for cancer risk assessment. Inflammatory status is also associated with ERs expression, but not with tumor growth or phenotype.

Expression of the estrogen receptor α, progesterone receptor and epidermal growth factor receptor in papillary thyroid carcinoma tissues

The present study aimed to determine the protein expression, in addition to the clinical value of the expression, of estrogen receptor α (ERα), progesterone receptor (PR) and epidermal growth factor receptor (EGFR) in papillary thyroid carcinoma (PTC). The expression of ERα, PR and EGFR was examined immunohistochemically on paraffin-embedded thyroid tissues obtained from 64 patients with PTC and 14 patients with nodular thyroid goiter (NTG). The expression level of ERα, PR and EGFR was found to be significantly elevated in the PTC tissues compared with the NTG tissues. In addition, the expression of ERα was found to be correlated with the size of PTC tumors. However, there was no significant difference between the expression levels of ERα, PR and EGFR in males and females with PTC. Thus, immunohistochemical evaluation of ERα, PR and EGFR expression in patients with PTC may aid in the prediction of the prognosis of patients with PTC.

Loss of ERβ expression in papillary thyroid carcinoma is associated with recurrence in young female

OBJECTIVES

We investigated the expression of oestrogen receptors (ERs) in papillary thyroid cancers (PTCs) and evaluated their prognostic role.

METHODS

We enrolled 81 female patients who underwent thyroid surgery and had a confirmed diagnosis of PTC between 01 January 1995 and 31 December 1996. Data on clinicopathologic parameters were obtained from patients' medical records. Tissue paraffin blocks of these 81 patients were collected for immunohistochemistry for ERα and ERβ.

RESULTS

ERα expression was observed in only eight patients (9·9%). In contrast, ERβ expression was positive in 36 (44·4%) patients. Total thyroidectomy (84·4% vs 61·1%, P = 0·017) and cervical lymph node metastasis (62·2% vs 22·2%, P = 0·000) were more frequent in the ERβ-negative group than in the ERβ-positive group. Among younger female patients (<45 years), the ERβ-negative group showed a tendency towards more frequent recurrent or persistent disease than the ERβ-positive group (42·3% vs 13·6%, P = 0·029). In contrast, the ERα-positive group showed more recurrent or persistent disease than the ERα-negative group in older female patients (100% vs 24·1%, P = 0·024). In multivariate analysis, ERβ negativity, extrathyroidal invasion and radioactive iodine treatment were risk factors for recurrence in young female patients.

CONCLUSION

Loss of ERβ expression was associated with recurrence in young female PTC patients. This finding suggests that oestrogen might play a protective role in the progression of PTC via ERβ, especially in young female patients.

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.

Obesity and thyroid cancer

Many studies have provided observational data on the association of obesity and thyroid cancers, but only few of them propose mechanisms that would permit a better understanding of the causal molecular mechanisms of this association. Considering that there is an increasing incidence of both obesity and thyroid cancers, we need to summarize and link recent studies in order to characterize and understand the contribution of obesity-related factors that might affect thyroid cancer development and progression. Adipose tissue is involved in many vital processes, including insulin sensitivity, angiogenesis, regulation of energy balance, activation of the complement system, and responses such as inflammation. Although these processes have their own molecular pathways, they involve the same molecules through which obesity and adipose tissue might exert their roles in carcinogenesis, not only affecting MAPK and PI3K or even insulin pathways, but also recruiting local inflammatory responses that could result in disease formation and progression. This review describes five important issues that might explain the link between excessive weight and thyroid cancer: thyroid hormones, insulin resistance, adipokines, inflammation, and sexual hormones.

Emerging molecular markers for the prognosis of differentiated thyroid cancer patients

Epithelial thyroid cancers are represented by the differentiated papillary and follicular thyroid carcinomas which, following dedifferentiation, are thought to give rise to the highly aggressive and incurable anaplastic thyroid carcinomas. Although derived from the same cell type, the different thyroid tumors show specific histological features, biological behavior and degree of differentiation as a consequence of different genetic alterations. Over the last few years, our knowledge regarding the molecular alterations underlying thyroid cell malignant transformation and cancer progression has considerably increased; however, the prognosis of differentiated thyroid cancer patients still relies on high-risk clinic-pathological variables. In particular, the actual staging systems provides only a rough prediction for cancer mortality and risk of recurrences, including in each risk group patients with highly different tumor-specific progression, disease-free interval and survival time. In order to improve DTC patient's risk stratification, both the European and the American Thyroid Associations proposed practical guidelines to integrate the actual staging systems with additional clinical features such as the tumor histological variant, the results of post-ablative whole body scan and the serum thyroglobulin levels. Despite that, patients within the same risk group still show a very heterogeneous behavior in terms of disease-free interval. As a consequence, the identification of new prognostic molecular biomarkers able to testify tumor aggressiveness is highly required. Here we'll review recently characterized new molecular markers potentially able to ameliorate the prognosis in DTC patients.

Benign breast and gynecologic conditions, reproductive and hormonal factors, and risk of thyroid cancer

The higher incidence of thyroid cancer in women compared with men suggests an influence of sex steroid hormones in the etiology of this malignancy. We investigated a comprehensive set of potential indicators of lifetime sex steroid hormone exposure in relation to thyroid cancer risk. Using data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, which enrolled 70,047 women, 50 to 78 years old, we prospectively examined associations of self-reported history of benign breast and gynecologic conditions, reproductive factors, and exogenous sex hormone use with thyroid cancer risk. Multivariable-adjusted HRs and 95% confidence intervals (CI) were calculated in models using age as the time metric. During follow-up (median, 11 years), 127 women were diagnosed with first primary thyroid cancer. Older age at natural menopause (≥55 vs. <50 years; HR, 2.24; 95% CI, 1.20-4.18), greater estimated lifetime number of ovulatory cycles (≥490 vs. <415 cycles; HR, 2.40; 95% CI, 1.33-4.30), greater number of live births (≥5 vs. 1-2; HR, 1.72; 95% CI, 1.05-2.82), and history of uterine fibroids (HR, 1.72; 95% CI, 1.18-2.50) were associated with an increased risk of thyroid cancer. Earlier age at menarche, greater number of reproductive years, history of a tubal ligation, and history of ovarian cysts were nonsignificantly associated with increased thyroid cancer risk. No associations were observed for oral contraceptive use, menopausal hormone therapy, or history of benign breast disease or endometriosis. In general, we found that factors reflecting a greater length of exposure to endogenous hormones, particularly during the reproductive years, were associated with risk of postmenopausal thyroid cancer.

Estrogens and stem cells in thyroid cancer

Recent discoveries highlight the emerging role of estrogens in the initiation and progression of different malignancies through their interaction with stem cell (SC) compartment. Estrogens play a relevant role especially for those tumors bearing a gender disparity in incidence and aggressiveness, as occurs for most thyroid diseases. Although several experimental lines suggest that estrogens promote thyroid cell proliferation and invasion, their precise contribution in SC compartment still remains unclear. This review underlines the interplay between hormones and thyroid function, which could help to complete the puzzle of gender discrepancy in thyroid malignancies. Defining the association between estrogen receptors' status and signaling pathways by which estrogens exert their effects on thyroid cells is a potential tool that provides important insights in pathogenetic mechanisms of thyroid tumors.

Obesity and thyroid cancer: epidemiologic associations and underlying mechanisms

The incidence of thyroid cancer has been rising over the past few decades along with a parallel increase in obesity. Observational studies have provided evidence for a potential association between the two. By contrast, clinical data for a link between type 2 diabetes mellitus, a condition strongly associated with obesity, and thyroid cancer are limited and largely not supportive of such an association. Obesity leads to hypoadiponectinemia, a pro-inflammatory state, and insulin resistance, which, in turn, leads to high circulating insulin and insulin-like growth factor-1 levels, thereby possibly increasing the risk for thyroid cancer. Thus, insulin resistance possibly plays a pivotal role in underlying the observed association between obesity and thyroid cancer, potentially leading to the development and/or progression of thyroid cancer, through its interconnections with other factors including insulin-like growth factor-1, adipocytokines/cytokines and thyroid-stimulating hormone. In this review, epidemiological and clinical evidence and potential mechanisms underlying the proposed association between obesity and thyroid cancer risk are reviewed. If the association between obesity and thyroid cancer demonstrated in observational studies proves to be causal, targeting obesity (and/or downstream mediators of risk) could be of importance in the prevention and management of thyroid cancer.

The cross-talk between estrogen receptor and peroxisome proliferator-activated receptor gamma in thyroid cancer

BACKGROUND

Estrogen receptor (ER) and peroxisome proliferator-activated receptor gamma (PPARγ) are associated with thyroid tumorigenesis and treatment. However, the interaction between them has not been studied.

METHODS

The impact of ER over-expression or down-expression by DNA/small interfering RNA (siRNA) transfection, ERα agonists, and the ERβ agonist diarylpropiolnitrile (DPN) on PPARγ expression/activity was examined in papillary thyroid carcinoma (PTC) and anaplastic thyroid carcinoma (ATC) cells. The effects of PPARγ modulation by rosiglitazone (RTZ), a PPARγ ligand, and of PPARγ siRNA on ER expression were determined. Cellular functions reflected by cell proliferation and migration were assayed. Apoptosis was analyzed by terminal deoxynucleotidyl transferase dUTP nick-end labeling, and apoptotic-related proteins were evaluated by Western blot analysis.

RESULTS

PPARγ protein and activity were reduced by the over-expression of either ERα or ERβ, whereas repression of ERα or ERβ increased PPARγ expression. The administration of RTZ counteracted the effects of ER and also reduced their expression, particularly in PTC cells. Moreover, knockdown of PPARγ increased ER expression and activity. Functionally, ERα activation offset the inhibitory effect of PPARγ on cellular functions, but ERβ activation aggregated it and induced apoptosis, particularly in PTC cells. Finally, the interaction between ERβ and PPARγ enhanced the expression of proapoptotic molecules, such as caspase-3 and apoptosis-inducing factor.

CONCLUSIONS

This study provides evidence supporting a cross-talk between ER and PPARγ. The reciprocal interaction between PPARγ and ERβ significantly inhibits the proliferation and migration of thyroid cancer cells, providing a new therapeutic strategy against thyroid cancer.

Obesity and metabolic comorbidities: environmental diseases?

Obesity and metabolic comorbidities represent increasing health problems. Endocrine disrupting compounds (EDCs) are exogenous agents that change endocrine function and cause adverse health effects. Most EDCs are synthetic chemicals; some are natural food components as phytoestrogens. People are exposed to complex mixtures of chemicals throughout their lives. EDCs impact hormone-dependent metabolic systems and brain function. Laboratory and human studies provide compelling evidence that human chemical contamination can play a role in obesity epidemic. Chemical exposures may increase the risk of obesity by altering the differentiation of adipocytes. EDCs can alter methylation patterns and normal epigenetic programming in cells. Oxidative stress may be induced by many of these chemicals, and accumulating evidence indicates that it plays important roles in the etiology of chronic diseases. The individual sensitivity to chemicals is variable, depending on environment and ability to metabolize hazardous chemicals. A number of genes, especially those representing antioxidant and detoxification pathways, have potential application as biomarkers of risk assessment. The potential health effects of combined exposures make the risk assessment process more complex compared to the assessment of single chemicals. Techniques and methods need to be further developed to fill data gaps and increase the knowledge on harmful exposure combinations.

Gender differences in cancer susceptibility: an inadequately addressed issue

The gender difference in cancer susceptibility is one of the most consistent findings in cancer epidemiology. Hematologic malignancies are generally more common in males and this can be generalized to most other cancers. Similar gender differences in non-malignant diseases including autoimmunity, are attributed to hormonal or behavioral differences. Even in early childhood, however, where these differences would not apply, there are differences in cancer incidence between males and females. In childhood, few cancers are more common in females, but overall, males have higher susceptibility. In Hodgkin lymphoma, the gender ratio reverses toward adolescence. The pattern that autoimmune disorders are more common in females, but cancer and infections in males suggests that the known differences in immunity may be responsible for this dichotomy. Besides immune surveillance, genome surveillance mechanisms also differ in efficiency between males and females. Other obvious differences include hormonal ones and the number of X chromosomes. Some of the differences may even originate from exposures during prenatal development. This review will summarize well-documented examples of gender effect in cancer susceptibility, discuss methodological issues in exploration of gender differences, and present documented or speculated mechanisms. The gender differential in susceptibility can give important clues for the etiology of cancers and should be examined in all genetic and non-genetic association studies.

Menstrual and reproductive factors, exogenous hormone use, and risk of thyroid carcinoma in postmenopausal women

PURPOSE

To investigate the association of reproductive factors and hormone therapy, including type of hormone therapy, with risk of thyroid cancer in postmenopausal women.

METHODS

We assessed these associations with risk of incident thyroid cancer in a cohort of 145,007 postmenopausal women enrolled in the Women's Health Initiative. Over 12.7 years of follow-up, 296 cases of thyroid cancer were identified, including 243 with papillary thyroid cancer. Cox proportional hazards models were used to estimate hazard ratios and 95 % confidence intervals for exposures of interest.

RESULTS

In both age-adjusted and multivariable-adjusted analyses, menstrual and reproductive factors including age at menarche, age at menopause, age at first birth, age at last live birth, parity, duration of breastfeeding, miscarriages, stillbirths, hysterectomy, bilateral oophorectomy, and use of oral contraceptives were not associated with risk of all thyroid cancer or papillary thyroid cancer. In addition, ever use of menopausal hormone therapy, current or former use, duration of use, and type were not associated with risk.

CONCLUSION

We found little support for associations of reproductive or hormonal factors with risk of developing thyroid cancer. Importantly, our study showed no association of type of hormone therapy used with thyroid cancer risk.