Estrogen promotes growth of human thyroid tumor cells by different molecular mechanisms

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.

Association between breastfeeding and breast, thyroid, and cervical cancer among Korean adult women: based on the Korean Genome and Epidemiology Study

Purpose

The purpose of this study was to explore the association between breastfeeding and the prevalence of breast, thyroid, and cervical cancer among Korean adult women.

Methods

The study was a secondary analysis of data from the Korea Genome and Epidemiology Study. The final samples were 113,944 Korean women among 173,205 urban-based cohort participants collected between 2004 and 2013 for adults aged forty and over. To determine the association between female cancers and breastfeeding experience, the number of childbirth, and total breastfeeding duration, logistic regression analysis was done. The demographic characteristics, health behavior, and female history were adjusted.

Results

The prevalence of breast cancer was 1.37 times higher in the non-breastfeeding group than in the breastfeeding group. Compared to having breastfed for more than 36 months, the prevalence of thyroid cancer was 1.68 times higher at breastfeeding for 13 to 36 months, 1.67 times higher at breastfeeding for 6 to 12 months, and 2.06 times higher at breastfeeding less than 6 months. Also, the prevalence of cervical cancer was 1.54 times higher at breastfeeding for 13 to 36 months, compared to breastfeeding for more than 36 months.

Conclusion

This study found that breastfeeding experience and a longer breastfeeding duration are associated with reduced risk of breast, thyroid, and cervical cancer in Korean women. It can be used as a basis for encouraging breastfeeding, and suggests further research on modifiable factors that reduce cancer risks.

Sex Bias in Differentiated Thyroid Cancer

Differentiated thyroid cancers are more frequent in women than in men. These different frequencies may depend on differences in patient's behavior and in thyroid investigations. However, an impact on sexual hormones is likely, although this has been insufficiently elucidated. Estrogens may increase the production of mutagenic molecules in the thyroid cell and favor the proliferation and invasion of tumoral cells by regulating both the thyrocyte enzymatic machinery and the inflammatory process associated with tumor growth. On the other hand, the worse prognosis of thyroid cancer associated with the male gender is poorly explained.

Thyroid diseases and second to fourth digit ratio in Polish adults

The association between second to fourth finger ratio and thyroid diseases is unexplained. There is a possible interaction between prenatal exposition to sex hormone and thyroid functions in the adulthood. The study included 175 adults investigated in Łódź in the central Poland. It consisted of two main parts: a survey including questions about occurrence of thyroid gland dysfunction and anthropometric measurements (body mass and height and length of the second and fourth finger, waist and hip circumferences). The women who had thyroid disease had higher 2D:4D digit ratio (left hand) (mean = 1.004; SD = 0.036) than healthy ones (mean = 0.989; SD = 0.030) (t = − 2105; p = 0.038; d = 0.707). The association between thyroid diseases occurrence and prenatal steroid hormone exposition is noticed. Only females who had thyroid diseases tend to have higher 2D:4D digit ratio, for left hand.

Evaluation of Children and Adolescents with Thyroid Nodules: A Single Center Experience

OBJECTIVE

We aimed to evaluate the clinical, radiological and pathological findings of children and adolescents with thyroid nodules.

METHODS

Data of 121 children and adolescent with thyroid nodules and had fine needle aspiration (FNA) were examined retrospectively. Concomitant thyroid disease, ultrasonography (US) features of the nodule, FNA and histopathological results were recorded. FNA results were assessed according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).

RESULTS

Median (range) age of the cases was 14 (3-18) years and 81% were female. FNA results of patients were: insufficient in 1 (0.8%); benign in 68 (56.2%); indeterminate in 44 (36.4%); and malignant in 8 (6.6%) patients. Among 39 patients who underwent surgery, 10 (25.6%) had differentiated thyroid cancer (DTC) and the overall malignancy rate was 10.0% (10/100). Follow-up FNA results showed progress based on TBSRTC in 18.7% of benign results and 4/75 patients had DTC on surgical excision. Two of 22 patients with atypia of undetermined significance (AUS) who continued follow-up was diagnosed with DTC. Male gender, presence of Hashimoto thyroiditis and US findings of uninodularity, hypoechogenicity, increased blood flow, irregular margins, solid structure, microcalcification and presence of abnormal cervical lymph nodes were associated with malignancy.

CONCLUSION

In this study 10% of thyroid nodules were malignant in children and adolescents. Patients with AUS have a 9% potential for malignancy. Patients with initially benign FNA result may have changes on repeat FNA when assessed with TBSTRC indicating a 5.3% false negative rate.

Prevalence and associated metabolic factors for thyroid nodules: a cross-sectional study in Southwest of China with more than 120 thousand populations

OBJECTIVE

To explore the prevalence and its associated metabolic factors of thyroid nodules (TNs) among subjects who participated in the physical examinations in Chongqing, China.

METHODS

The participants from the Health Management Center of JinShan Hospital of Chongqing Medical University, between September 2015 and May 2020, were included in this study. All of the participants underwent thyroid ultrasonography, anthropometric measurements, and serum examinations. Differences in the TNs prevalence were compared with the chi-square test or Wilcoxon rang-sum test. Multivariable logistic regression analyses were used to estimate the metabolic factors associated with TNs and multiple thyroid nodules (MTNs).

RESULTS

Of the included 121,702 participants, 41,547 had TNs, and 20,899 had MTNs, with the prevalence of 34.1 and 17.0 %, respectively. Women had a significantly higher prevalence of TNs than men (40.6 % vs. 29.8 %; χ² = 1517.33, P < 0.001), and TNs prevalence was gradually increased with age (P for trend < 0.001). Female gender, advanced age, and metabolic factors including central obesity, hypertension, diabetes and fatty liver were positively associated with TNs; BMI, hyperlipoidemia and hyperuricemia were not independent risk factors of TNs. While female gender, advanced age, central obesity, hypertension and diabetes were independent risk factors of MTNs.

CONCLUSIONS

The prevalence of thyroid nodules was relatively high. The associated factors identified in this study could help the clinicians to detect the high-risk patients and make targeted screening strategies for the preventing of the occurrence of TNs.

Metabolic syndrome and its components are associated with thyroid volume in adolescents

OBJECTIVE

To explore the association between metabolic syndrome (MetS) and its component and thyroid volume in Chinese adolescents, and to compare the detection rate of MetS under the three different diagnostic criteria.

METHODS

A total of 1097 school students (610 males and 487 females, ages 12-15 years) were enrolled. All the participants underwent physical examination, biochemical test, and thyroid gland ultrasonography. The thyroid volume of normal, overweight and obese group was compared. We also analyzed the association between the number of MetS components and thyroid volume. Linear and multiple linear regression were applied to explore the association between metabolic parameters and thyroid volume.

RESULTS

The thyroid volume of the males in overweight (t = 3.784, P < 0.001) and obese group (t = 5.068, P < 0.001) was significantly larger than that in normal group; the thyroid volume of the females in overweight group (t = 4.627,P < 0.001) was significantly larger than that of normal group. As the number of MetS components increased, the thyroid volume also increased significantly (F = 10.64, P < 0.01). Height, weight, body mass index (BMI), waist circumference, hip circumference, systolic blood pressure, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), uric acid and triglyceride were all positively associated with thyroid volume in the adolescents (P all < 0.001). Meanwhile, there was a negative association between high-density lipoprotein cholesterol (HDL-C) and thyroid volume (P < 0.001). According to multiple linear regression, waist circumference (β = 0.029, 95 %CI: 0.015 ~ 0.042; P < 0.01) and waist height ratio (β = 3.317, 95 %CI: 1.661 ~ 4.973; P < 0.01) were predict factors of thyroid volume. No statistical difference was found in the detection rates of metabolic syndrome under the three diagnostic criteria.

CONCLUSIONS

Overweight, obesity and metabolic syndrome was associated with adolescent thyroid volume. Central obesity may be an independent risk factor for thyroid enlargement in adolescents.

Androgen Activity Is Associated With PD-L1 Downregulation in Thyroid Cancer

Thyroid cancer is the most prevalent endocrine malignancy in the United States with greater than 53,000 new cases in 2020. There is a significant gender disparity in disease incidence as well, with women developing thyroid cancer three times more often than men; however, the underlying cause of this disparity is poorly understood. Using RNA-sequencing, we profiled the immune landscape of papillary thyroid cancer (PTC) and identified a significant inverse correlation between androgen receptor (AR) levels and the immune checkpoint molecule PD-L1. The expression of PD-L1 was then measured in an androgen responsive-thyroid cancer cell line. Dihydrotestosterone (DHT) treatment resulted in significant reduction in surface PD-L1 expression in a time and dose-dependent manner. To determine if androgen-mediated PD-L1 downregulation was AR-dependent, we treated cells with flutamide, a selective AR antagonist, and prior to DHT treatment to pharmacologically inhibit AR-induced signaling. This resulted in a > 90% restoration of cell surface PD-L1 expression, suggesting a potential role for AR activity in PD-L1 regulation. Investigation into the AR binding sites showed AR activation impacts NF-kB signaling by increasing IkBα and by possibly preventing NF-kB translocation into the nucleus, reducing PD-L1 promoter activation. This study provides evidence of sex-hormone mediated regulation of immune checkpoint molecules in vitro with potential ramification for immunotherapies.

Signal Pathway of Estrogen and Estrogen Receptor in the Development of Thyroid Cancer

The molecular mechanisms underlying the development of thyroid cancer (TC) have been examined through extensive experiments. A large number of studies have shown that the incidences of thyroid cancer in women is much higher than that in men, so estrogen plays a key role in the development of thyroid cancer. Estrogen plays its growth-promoting role through classical genomic and non-genomic pathways mediated by membrane-bound estrogen receptors. It also can affect tumor progression by regulating the tumor microenvironment. We summarize the understanding of molecular mechanisms of estrogen signaling pathways in thyroid cancer. Furthermore, it will provide a new target for the treatment of thyroid carcinoma by blocking estrogen and its related action pathway.

Evaluation of the relationship between previous statin use and thyroid cancer using Korean National Health Insurance Service-Health Screening Cohort data

The association of thyroid cancer with statin use is controversial. This study aimed to investigate the association of previous statin use with thyroid cancer in the ≥ 40-year-old population in the Korean National Health Insurance Service-Health Screening Cohort. The 5501 patients in the thyroid cancer group were matched with the 22,004 patients in the non-thyroid cancer group for age, sex, income, and region of residence. Previous statin use during the 2 years before the diagnosis of thyroid cancer was examined. The odds ratios (ORs) with 95% confidence intervals (CIs) of previous statin use for thyroid cancer were estimated using conditional logistic regression analyses. Additionally, subgroup analyses were conducted. The thyroid cancer group showed more days of previous statin use than the non-thyroid cancer group (72.3, standard deviation [SD] = 181.2 days vs. 64.3, SD = 174.4 days, P = 0.003). Although the odds of previous statin use for thyroid cancer were high in the crude model (OR = 1.10, 95% CI 1.04–1.17, P = 0.002), they were low in the fully adjusted model (OR = 0.89, 95% CI 0.82–0.95, P = 0.001). According to age and sex subgroups, the younger (< 60 years old) male group showed lower odds for thyroid cancer according to previous statin use (adjusted OR = 0.70, 95% CI 0.55–0.88, P = 0.003), but this finding was not observed in other subgroups of older men or in any groups of women. Thyroid cancer was negatively associated with statin use in the previous 2 years in the adjusted model.

Pituitary neuroendocrine tumors and differentiated thyroid cancer: do metabolic and inflammatory risk factors play roles?

PURPOSE

It is postulated that patients with different types of pituitary neuroendocrine tumors (PitNETs) may present a higher incidence of cancer. Factors underlying individuals becoming overweight, such as insulin resistance, hyperleptinemia, and low-grade inflammation, may play a role in the risk of differentiated thyroid carcinoma (DTC) in such patients. This study aimed to investigate the frequency of and obesity-related risk factors associated with DTC in patients with PitNETs.

METHODS

This cross-sectional study involved 149 patients with nonacromegalic PitNETs (AG group), 71 patients with acromegaly (ACRO group), and 156 controls (CG group). All participants underwent insulin and blood glucose measurements with the determination of the homeostatic model assessment-insulin resistance (HOMA-IR) index, leptin, and high-sensitivity C-reactive protein (hsCRP), and they also underwent thyroid ultrasound. Clinically significant nodules were biopsied for subsequent cytopathological evaluation, and participants were operated on when indicated.

RESULTS

Patients in the AG group had high levels of insulin resistance and significantly higher levels of leptin and hsCRP compared with those of patients in the ACRO group. There were no cases of DTC in the AG group; two findings, one incidental, of DTC occurred in the CG group, and three cases of DTC were present in the ACRO group. Acromegaly was associated with DTC after adjusted analysis.

CONCLUSIONS

Our findings in patients with nonacromegalic PitNETs do not indicate a high risk for DTC despite the presence of metabolic and inflammatory risk factors for neoplastic events. In contrast, acromegaly promotes a greater risk of DTC.

Assessment of the Thyroid Functions among Female Flight Attendants

Introduction: Epidemiological observations indicate that stewardesses are exposed to reproductive and endocrine system disturbances. The aim of the study was to assess of thyroid function disturbances as well as to identify factors affecting the thyroid function among stewardesses working both within one time zone and on long-distance flights. Material and methods: The cross-sectional study covered 103 women aged 23–46. The study group (I) was divided into two subgroups: group Ia comprising stewardesses flying within one flight zone and group Ib stewardesses working on long-distance flights. The control group (II) were women of reproductive age who sought medical assistance due to marital infertility in whom the male factor was found to be responsible for problems with conception in the course of the diagnostic process. The assessment included: age, BMI, menstrual cycle regularity, length of work, frequency of flying, thyroid stimulating hormone (TSH) concentration, level of free thyroxine (fT4), antibodies to thyroglobulin (aTG) and to thyroperoxidase (aTPO), prolactin concentration, sex hormone binding globulin (SHGB) concentration, total cholesterol, and low density lipoprotein (LDL) fraction. Descriptive methods and inferential statistics methods were used to compile the data. Results: The difference between the concentrations of TSH in the study group (2.59 mcIU/mL) and the control group (1.52 mcIU/mL) was statistically significant (p < 0.01). An elevated titer of thyroid antibodies (aTPO and/or aTG) was revealed in 46.3% of stewardesses and in 15.1% of patients from the control group (p < 0.001). Groups Ia and Ib in individual concentrations were not statistically significant. The frequency of occurrence of an elevated titer of thyroid antibodies depended on the length of work in the study group (p > 0.05). No statistically significant difference was found in patients spending up to 60 h a month flying and in patients spending more than 60 h flying, the percentage of the occurrence of thyroid antibodies was 50% and 43.5, respectively. Conclusions: The occurrence in stewardesses of a higher TSH concentration than in the control group can signify that stewardesses are burdened with a higher risk of the development of hypothyroidism in the future. The character of the work of stewardesses (frequency of flying as well as length of work) does not affect the immunological profile of the thyroid.

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.

Menstrual, reproductive and hormonal factors and thyroid cancer: a hospital-based case-control study in China

BACKGROUND

There have been considerable studies on the effects of reproductive factors on thyroid cancer risk, while findings are inconsistent. In this analysis, we aimed to investigate the associations between menstrual, reproductive and hormonal factors with thyroid cancer occurrence in a population of Chinese women.

METHODS

Using data from a 1:1 matched case-control study performed between 2015 and 2017 in Zhejiang Province of China, a second analysis of 2261 pairs of female subjects was conducted. The possible effects for thyroid cancer were evaluated in logistic regression models by odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Later age at first pregnancy (for > 25 vs. ≦ 20 years, OR: 0.47, 95% CI 0.23-0.96) and longer duration of breast feeding (for 6-12 vs. ≦ 6 months, OR: 0.49, 95% CI 0.24-0.98) were significantly associated with decreased occurrence of thyroid cancer, while no trend was observed. Stratified by age at enrollment, only the association with duration of breast feeding remained significant, but limited to younger women (≦ 50 years).

CONCLUSIONS

Our results suggested that women with later age at first pregnancy or longer breast feeding duration were less likely to have thyroid cancer. These findings supported an influence role of reproductive factors in thyroid cancer risk.

The Relationship and Gender Disparity Between Thyroid Nodules and Metabolic Syndrome Components Based on a Recent Nationwide Cross-Sectional Study and Meta-Analysis

BACKGROUND

Metabolic syndrome (MetS) has a potential connection with thyroid disease, but its relationship with thyroid nodules (TNs) is still controversial. This study aims to clarify the relationship between MetS and TNs, and this relationship in the subgroup of gender.

METHODS

The recent nationwide cross-sectional study called Thyroid Disorders, Iodine Status, and Diabetes Epidemiological survey provided the newest data on the relationship between MetS and TNs from China and included 56,729 subjects. We also researched related literature in PubMed, EMBASE, Cochrane Library, and MEDLINE until Oct 30, 2020, in order to perform a meta-analysis. The relevant articles were examined, and the eligible studies were included to assess the association between MetS and TNs.

RESULTS

The meta-analysis included 15 studies (involving 468,845 subjects). Of these, 14 studies were from the databases, and one study was this cross-sectional data. The meta-analysis showed that TNs were associated with a higher prevalence of MetS (OR=1.87, 95% CI: 1.44-2.45) and the components of MetS, including central obesity (OR=1.41, 95% CI: 1.15-1.72), hypertriglyceridemia (OR=1.13, 95% CI: 1.10-1.15), low high-density lipoprotein cholesterolemia (OR=1.11, 95% CI: 1.02-1.20), abnormal blood pressure (OR=1.68, 95% CI: 1.62-1.75), and hyperglycemia (OR=1.59, 95% CI: 1.46-1.74). Central obesity displayed gender differences, being a risk factor in males (OR=1.38, 95% CI: 1.02-1.86) but not in females (OR=1.47, 95% CI: 0.97-2.23).

CONCLUSION

TNs were indeed associated with a higher prevalence of MetS. In addition, its component diseases, such as central obesity, hypertriglyceridemia, abnormal blood pressure, and hyperglycemia, were also associated with TNs. Females with MetS or its components had a higher risk of suffering from TNs than males.

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.

Association between Urinary Iodine Concentration and Thyroid Nodules in Adults: A Cross-Sectional Study in China

Background

Associations between iodine intake and thyroid nodules (TNs) were not consistent. We aimed to illustrate the relationship between urinary iodine concentration (UIC) and TNs.

Methods

A total of 12,698 participants were enrolled in analysis. All of the participants filled out questionnaires and underwent physical examinations, laboratory tests, and thyroid ultrasonography. UIC, serum thyrotropin (TSH), thyroid peroxidase antibodies (TPOAb), and thyroglobulin antibodies (TgAb) were measured in the central laboratory.

Results

The prevalence of TNs was 16.00%, and the median UIC was 206.1 μg/L. TNs and UIC were negatively related when UIC was less than 527 μg/L (adjusted OR = 0.87; 95% CI, 0.80, 0.94), and the relationship between UIC and TNs was not statistically significant when UIC was greater than 527 μg/L (adjusted OR = 1.25; 95% CI, 0.98, 1.60). In women, UIC was negatively associated with risk for TNs (adjusted OR 0.95; 95% CI, 0.91, 0.99).

Conclusion

The relationship between TNs and UIC differed between men and women. The risk of TNs decreased with the elevation of UIC in men when UIC was lower than 527 μg/L, while UIC and the presence of TNs were negatively correlated in women. In the future, cohort studies or other studies that can explain causality must be conducted to explore the relationship between iodine status and TNs.

Association of breastfeeding with thyroid function and autoimmunity in postmenopausal women

OBJECTIVE

Whether breastfeeding influences thyroid function and autoimmunity is not elucidated. We examined the association of history of breastfeeding with thyroid hormones and thyroperoxidase antibody (TPOAb).

DESIGN

Cross-sectional study of data from the 2013-2015 Korea National Health and Nutrition Examination Survey.

METHODS

A total of 816 postmenopausal women were stratified into three groups according to the duration of breastfeeding and number of breastfed children. Thyroid hormones levels, TPOAb titers, and the prevalence of hypothyroidism and TPOAb positivity were evaluated in each group.

RESULTS

Subjects with a history of prolonged breastfeeding had lower levels of thyrotropin (TSH) and TPOAb than the others. After adjusting for multiple confounding factors, the estimated means of TSH and TPOAb were associated with cumulative duration of breastfeeding. Duration of breastfeeding per child was associated with TSH levels, and number of breastfed children was associated with TPOAb titers. The odds ratio (OR) of hypothyroidism was significantly lower in group for ≥36 months of cumulative duration of breastfeeding, and the OR of TPOAb positivity was significantly lower in group with ≥3 breastfed children. In addition, duration of breastfeeding and the number of breastfed children were linearly correlated with log TSH and TPOAb each other in the multivariate model.

CONCLUSIONS

The present study showed that prolonged breastfeeding was inversely associated with TSH and the prevalence of hypothyroidism. Moreover, TPOAb and the prevalence of TPOAb positivity were inversely associated with number of breastfed children. These results indicate that breastfeeding may exert a protective effect on thyroid function and autoimmunity.

Obesity is positively related and tobacco smoking and alcohol consumption are negatively related to an increased risk of thyroid cancer

The purpose of this study was to evaluate the relationships of smoking, alcohol consumption, and obesity with thyroid cancer in Korean residents. The Korean National Health Insurance Service-Health Screening Cohort includes individuals ≥ 40 years who were assessed from 2002 to 2013. In total, 4977 thyroid cancer participants were matched with respect to age, sex, income, and region of residence with 19,908 controls at a ratio of 1:4. Crude and adjusted (for the Charlson comorbidity index, smoking status, frequency of alcohol consumption, and obesity) odds ratios (ORs) were analyzed using conditional logistic regression analyses. Additionally, 95% confidence intervals (CIs) were calculated. The adjusted OR of smoking for thyroid cancer was 0.62 (95% CI 0.54–0.72, P < 0.001), and that of alcohol consumption was 0.83 (95% CI 0.75–0.92, P < 0.001). The adjusted ORs of the BMI categories were 1.13 (95% CI 1.05–1.22, P = 0.002) for obese I, and 1.24 (95% CI 1.04–1.47, P = 0.014) for obese II. The ORs of smoking and alcohol consumption were lower, and those of overweight and obesity were higher in thyroid cancer patients than in individuals in the control group.

Risk of second primary breast cancer among cancer survivors: Implications for prevention and screening practice

Second primary breast cancer (SPBC) is becoming one of the major obstacles to breast cancer (BC) control. This study was aimed to determine the trend of SPBC incidence over time and the risk of developing SPBC in site-specific primary cancer survivors in the United States. The Surveillance, Epidemiology, and End Results (SEER) 13 registry (1992-2015) was used to identify SPBC patients with previous malignancies. Standardized incidence ratio (SIR) was computed to compare the incidence rates of the observed cases of SPBC in cancer survivors over the expected cases in the general population. Elevated risk of SPBC was observed in women with previous BC (SIR = 1.74) or thyroid cancer (SIR = 1.17). Women with initial skin melanoma in older age (≥50 years) (SIR = 1.11), or White race (SIR = 1.11) presented an elevated incidence of SPBC than the general female population. Besides, Asian/Pacific Islander (API) women with cancer of corpus uteri, ovary, bladder, or kidney were prone to developing SPBC when compared with the general population, with SIRs of 1.61, 1.35, 1.48, and 1.70, respectively. Male BC patients showed profound risk of developing SPBC (SIR = 34.86). Male leukemia patients also presented elevated risk of developing SPBC (SIR = 2.06). Our study suggests significant increase of SPBC in both sexes in the United States. Elevated risk of SPBC exists in survivors with primary BC, female thyroid cancer, male leukemia, and API female cancer patients with primary genitourinary cancer. Our study is helpful in developing strategies for BC control and prevention on specific first primary cancer survivors with an elevated risk of SPBC.

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.

Adolescent overweight and obesity and the risk of papillary thyroid cancer in adulthood: a large-scale case-control study

This study aimed to investigate the association between adolescent overweight and obesity and PTC risk in adulthood. We conducted a case-control study in the Republic of Korea with 1,549 PTC patients and 15,490 controls individually matched for age and sex. We estimated body mass index (BMI) at age 18 years from self-reported weight at this age. Compared with BMI < 23.0 at age 18 years, BMI ≥ 25.0 at age 18 years was associated with higher PTC risk (odds ratio [OR] = 4.31, 95% confidence interval [CI]: 3.57, 5.22). The association between BMI ≥ 25.0 at age 18 years and PTC risk was stronger among men (OR = 6.65, 95% CI: 4.78, 9.27) than among women (OR = 3.49, 95% CI: 2.74, 4.43), and stronger among individuals with current BMI ≥ 25.0 (OR = 8.21, 95% CI: 6.34, 10.62) than among those with current BMI < 25.0 (OR = 2.21, 95% CI: 1.49, 3.27). Among PTC patients, BMI ≥ 25.0 at age 18 years was associated with extra-thyroidal extension and T stage ≥2, but not with N stage ≥1 or BRAF^V600E mutation. Adolescent overweight and obesity was associated with higher risk of PTC in adulthood. Our results emphasise the importance of weight management in adolescence to decrease the PTC risk.

Association of Changes in Metabolic Syndrome Status With the Incidence of Thyroid Nodules: A Prospective Study in Chinese Adults

Although several cross-sectional studies have shown an association of metabolic syndrome (MetS) with nodular thyroid disease, related prospective studies are scarce. This study investigated the association of MetS with thyroid nodule (TN) incidence in Chinese adults, and explored whether the development of or recovery from MetS is associated with changes in the risk of developing TNs. A total of 4,749 Chinese aged 18-65 years were involved in this 6-year prospective study. The association of MetS with TN prevalence was examined. TN-free individuals at baseline (n = 3,133) were further examined. TN incidence rates in groups with different MetS statuses (MetS-free, MetS-developed, MetS-recovery and MetS-chronic) were analyzed. Of all participants, 18.21 and 31.65% had MetS and TNs, respectively. MetS patients had a higher TN prevalence than the non-MetS group (31.08 vs. 19.81% in males, p < 0.01; 59.52 vs. 39.59% in females, p < 0.01). Sex, age and MetS were independent risk factors for TNs. At a median follow up of 5.94 years, the MetS-chronic group (4.37/100 person-years) had a higher risk of TNs (adjusted incidence rate ratio [IRR] = 1.288 [95% CI 1.014-1.636]) compared with the MetS-free group (2.72/100 person-years) in the whole cohort. In males, the MetS-chronic group (3.76/100 person-years) had a higher risk of TNs (adjusted IRR = 1.367 [95% CI 1.017-1.835]) compared with the MetS-free group (2.31/100 person-years). In females, the risk of TNs was significantly higher in the MetS-chronic (6.44/100 person-years) and MetS-developed (6.31/100 person-years) groups compared with the MetS-free group (3.23/100 person-years).

Deciphering Adverse Outcome Pathway Network Linked to Bisphenol F Using Text Mining and Systems Toxicology Approaches

Bisphenol F (BPF) is one of several Bisphenol A (BPA) substituents that is increasingly used in manufacturing industry leading to detectable human exposure. Whereas a large number of studies have been devoted to decipher BPA effects, much less is known about its substituents. To support decision making on BPF's safety, we have developed a new computational approach to rapidly explore the available data on its toxicological effects, combining text mining and integrative systems biology, and aiming at connecting BPF to adverse outcome pathways (AOPs). We first extracted from different databases BPF-protein associations that were expanded to protein complexes using protein-protein interaction datasets. Over-representation analysis of the protein complexes allowed to identify the most relevant biological pathways putatively targeted by BPF. Then, automatic screening of scientific abstracts from literature using the text mining tool, AOP-helpFinder, combined with data integration from various sources (AOP-wiki, CompTox, etc.) and manual curation allowed us to link BPF to AOP events. Finally, we combined all the information gathered through those analyses and built a comprehensive complex framework linking BPF to an AOP network including, as adverse outcomes, various types of cancers such as breast and thyroid malignancies. These results which integrate different types of data can support regulatory assessment of the BPA substituent, BPF, and trigger new epidemiological and experimental studies.

Thyroid function among women with gestational trophoblastic diseases. A cross-sectional study

BACKGROUND

Gestational trophoblastic diseases (GTDs) are treatable rare tumors with wide distribution. The estimated incidence of GTDs varies dramatically between different regions globally. In early pregnancy, there may be high human chorionic gonadotropin (HCG) concentrations, normal or slightly increased free T4 (fT4) and subnormal thyroid-stimulating hormone (TSH), causing hyperthyroidism ranging from subclinical to severe. Beta-HCG causes thyrotoxicosis through thyroid stimulation in patients with trophoblastic tumors.

OBJECTIVE

To assess thyroid function among patients diagnosed with complete or partial hydatidiform mole, within the GTD spectrum.

DESIGN AND SETTING

Cross-sectional study based on patients' medical records at Van University Hospital, Van, Turkey.

METHODS

50 patients monitored due to diagnoses of hydatidiform mole were included and were examined regarding thyroid function. Thyroid gland size and volume were measured using thyroid ultrasonography. Beta-HCG, TSH, fT4, free T3 (fT3), total T4 (TT4), total T3 (TT3), anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG) and thyroglobulin levels were measured.

RESULTS

Among these patients, 15 (30%) were diagnosed with complete hydatidiform mole and 35 (70%) with partial hydatidiform mole, according to pathology results. Those with complete hydatidiform mole were older (P = 0.003), with higher number of pregnancies (P = 0.032), lower TSH level (P = 0.011) and higher fT4 and TT4 levels (P = 0.04; P = 0.028), compared with partial hydatidiform mole patients.

CONCLUSION

In hydatidiform mole patients, thyroid disease severity increases with age, parity, beta-HCG level and mole size. However, prospective multicenter studies on this topic are needed, with larger numbers of patients and closer monitoring.

Role of phospho-ezrin in differentiating thyroid carcinoma

Comprehensive theory explaining the relationship between estrogen (E2) and ezrin in metastasis of thyroid cancer remains non-elicited. In vitro results revealed that E2 could stimulate the expression and phosphorylation of ezrin in a time and dose dependent manner. Our data clearly showed that E2 enhanced the migration and invasion of cells, which was reversed by the transfection of cells with ezrin specific siRNA. Further, we observed that Phosphoinositide 3-kinase (PI3K) ROCK-2 are among the kinases responsible for E2 induced phosphorylation of ezrin. Clinical validation of ezrin/phospho-ezrin revealed that phospho-ezrin was intensely expressed in follicular thyroid carcinoma (FTC) and follicular variant of papillary thyroid carcinoma (FVPTC), while it was completely absent in follicular adenoma (FA) lesions in which the differentiation of the follicular neoplasms remains subtle. When histology of different carcinomas is correlated with benign FA with respect to phospho-ezrin, we observed that the marker was highly significant (p = 0.0001). 100% sensitivity, specificity and diagnostic accuracy of the above marker in the histological association of FTC, FVPTC with FA, enables us to suggest phospho-ezrin as a diagnostic marker to differentiate the follicular neoplasms. These data are the first to suggest the dynamic regulation of ezrin phosphorylation during metastasis in FTC.

The Emerging Role of Estrogens in Thyroid Redox Homeostasis and Carcinogenesis

Reactive oxygen species (ROS) are the most critical class of free radicals or reactive metabolites produced by all living organisms. ROS regulate several cellular functions through redox-dependent mechanisms, including proliferation, differentiation, hormone synthesis, and stress defense response. However, ROS overproduction or lack of appropriate detoxification is harmful to cells and can be linked to the development of several diseases, such as cancer. Oxidative damage in cellular components, especially in DNA, can promote the malignant transformation that has already been described in thyroid tissue. In thyrocyte physiology, NADPH oxidase enzymes produce large amounts of ROS that are necessary for hormone biosynthesis and might contribute to the high spontaneous mutation rate found in this tissue. Thyroid cancer is the most common endocrine malignancy, and its incidence is significantly higher in women than in men. Several lines of evidence suggest the sex hormone estrogen as a risk factor for thyroid cancer development. Estrogen in turn, besides being a potent growth factor for both normal and tumor thyroid cells, regulates different mechanisms of ROS generation. Our group demonstrated that the thyroid gland of adult female rats exhibits higher hydrogen peroxide (H₂O₂) production and lower enzymatic antioxidant defense in comparison with male glands. In this review, we discuss the possible involvement of thyroid redox homeostasis and estrogen in the development of thyroid carcinogenesis.

Sexual Dimorphism of NADPH Oxidase/H₂O₂ System in Rat Thyroid Cells; Effect of Exogenous 17β-Estradiol

It has long been observed that females are more susceptible to thyroid diseases than males. Epidemiological and experimental data show that actions of hormonal factors—especially estrogens—may explain such disparity. However, the exact cause and mechanisms of this sexual dimorphism remain so far unknown. Therefore, we aimed at evaluating the effect of 17β-estradiol on the redox balance in thyroids of male and female rats. Expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, i.e., dual oxidase 1 (DUOX1), dual oxidase 2 (DUOX2) and NADPH oxidase 4 (NOX4), and hydrogen peroxide (H₂O₂) levels were evaluated in the primary cell cultures derived from thyroid glands of adult male or female Wistar rats. The measurement was made before and after treatment with 17β-estradiol alone or with addition of one of its receptor antagonists. We found that under basal conditions female thyroid cells are exposed to higher concentrations of H₂O₂, most likely due to NOX/DUOX enzymes activity. Additionally, exogenous 17β-estradiol stimulated NOX/DUOX expression as well as H₂O₂ production, and this effect was mainly mediated through ERα. In conclusion, oxidative processes may constitute mechanisms responsible for sexual dimorphism of thyroid diseases. Exogenous 17β-estradiol may play a crucial pathogenic role in thyroid diseases via oxidative mechanisms, however without any gender differences.

Fertility Drugs Associated with Thyroid Cancer Risk: A Systematic Review and Meta-Analysis

Associations have been demonstrated between fertility drugs and a variety of hormone-sensitive carcinomas. The purpose of this study was to determine the relationship between fertility drugs used in the treatment of female infertility and the risk of thyroid cancer. To investigate the clinical significance of fertility drugs used for the treatment of female infertility and the risk associated with thyroid cancer, we performed a literature search using PubMed, MEDLINE, the Cochrane Library, the Web of Science, and EBSCOHOST for comparative studies published any time prior to July 21, 2017. The studies included women who were treated for infertility with fertility drugs, such as clomiphene citrate, gonadotropins, or other unspecified fertility agents, which reported the incidence of thyroid cancer as the main outcome. Eight studies were included in the meta-analyses. Among women with infertility, there was a significant positive association between thyroid cancer risk and the use of fertility drugs (relative risk [RR] = 1.35; 95% confidence interval [CI] 1.12–1.64; P = 0.002). Additionally, among women with infertility, the use of clomiphene citrate was associated with an increased risk of thyroid cancer compared to women who did not use fertility drugs (RR = 1.45; 95% CI 1.12–1.88; P = 0.005). After pooling results, we found that the parity status of infertile women using fertility drugs was not associated with thyroid cancer risk (RR = 0.99; 95% CI 0.61–1.58, P = 0.95). In summary, clomiphene citrate (the most commonly used fertility drug) and other fertility drugs are associated with an increased risk of thyroid cancer.

Risk of thyroid cancer in relation to height, weight, and body mass index in Japanese individuals: a population-based cohort study

Greater height and body mass index (BMI) have been associated with an increased risk of thyroid cancer incidence in Western countries. However, few epidemiological studies have assessed the association between anthropometric factors, such as BMI, height, or weight, and thyroid cancer incidence in Asian populations. Using the population‐based Japan Public Health Center‐based prospective study database, we investigated the relationship between anthropometric factors and thyroid cancer incidence. Data on anthropometric factors were collected through a self‐administered questionnaire at baseline. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the Cox proportional hazards model, and the exposure level was categorized into quintiles. A total of 49,062 men and 53,661 women enrolled between 1990 and 1994 were included in our analyses, and 191 cases (37 in men and 154 in women) of thyroid cancer were identified, with 1,695,702 person‐years of follow‐up until 2010. Compared with the male group with height ≤160 cm, HRs of the male groups with height 165–168 cm and ≥169 cm were 3.92 (95% CI; 1.33–11.55, P = 0.013) and 4.24 (95% CI; 1.32–13.61, P = 0.015), respectively, and the HR per 5‐cm increase in height was 1.12 (95% CI 1.06–1.18, P < 0.001). In contrast, the association between anthropometric features and the risk of thyroid cancer did not significantly differ among women. In this population, an increase in risk for increased height was observed in men, but no associations between anthropometric indexes and thyroid cancer risk were observed in women.

Characteristics and survival of patients with metachronous or synchronous double primary malignancies: breast and thyroid cancer

BACKGROUND

Clinical experiences suggest that breast cancer (BC) and thyroid cancer (TC) occur metachronously or synchronously in a patient more frequently than it would by chance. This study was conducted to investigate the clinicopathological characteristics and survival of these double primary malignancies.

METHODS

18732 patients with first primary BC and 12877 female patients with first primary TC were performed in this retrospective case-controlled study. The control groups were matched with both age at diagnosis and time of surgery (±2 years). The clinicopathological factors, Overall survival (OS), and HRs were evaluated by SPSS.

RESULTS

There were 91(0.49%) BC patients developed metachronous second primary TC (B-T group), and 117 (0.91%) TC patients developed metachronous second primary BC (T-B group).The expression of estrogen and progesterone receptors, and the value of Ki-67, were significantly higher in the B-T group than control. The median value of thyroid globulin antibody (TGAb) and thyroid peroxidase antibody (TPOAb) were higher in T-B group than control (p <0.05). The duration before second primary cancer was shorter for the B-T group than the T-B group (4.09 years vs. 5.82 years, p<0.001). B-T group patients showed poorer survival than BC only patients (p=0.044).

CONCLUSIONS

In general, the overall risk of the occurrence of a second primary TC or BC elevated highly in patients with BC or TC. Detailed mechanisms need to be studied to explore the association between these two cancers. Early detection and effective prevention for the first primary BC or TC patients are necessities for reducing the incidence of the second primary cancer and improving the OS.

Clinical-pathological Characteristics and Prognostic Factors for Papillary Thyroid Microcarcinoma in the Elderly

Background: The incidence of papillary thyroid microcarcinoma (PTMC) has increased dramatically over the past three decades worldwide. The annual rate of increase in the elderly (≥65) PTMC patients is 1.4 times higher than that in the adult (<65) PTMC patients. The aim of the present study is to identify the clinical-pathological characteristics and prognostic factors in the elderly PTMC patients.

Methods: The source population is PTMC patients whose information is available in the Surveillance, Epidemiology and End Results (SEER) database (2004-2013). We analyzed specific selected clinical-pathological parameters and prognostic factors for the PTMC patients who were aged 65 or above (N=4812).

Results: Within the elderly group, the male patients, in comparison to the females, had a higher percentage of lymph-node metastases (5.29% vs. 12.27%, P < 0.001), distant metastasis (0.27% vs. 1.07%, P < 0.001), and stage III-IV tumors (9.19% vs. 15.85%, P < 0.001). Moreover, the elderly patients had a lower median cause-specific survival (CSS) compared with the adult patients (P < 0.001). Stage III-IV disease (hazard ratio (HR): 8.064, P < 0.001) was a strong risk factor for PTMC CSS. Being female (HR: 0.440, P = 0.011), total thyroidectomy (HR: 0.057, P = 0.001), and lobectomy (HR: 0.058, P < 0.001) were all strong protectors of PTMC CSS.

Conclusion: Thyroidectomy improved CSS of the elderly PTMC patients. Compared with thyroid lobectomy, total thyroidectomy did not increase CSS for the elderly PTMC patients. The elderly PTMC patients who received radio therapy did not experience an increase in CSS.

Female Reproductive Factors and Differentiated Thyroid Cancer

Differentiated thyroid cancer (DTC) is markedly more common in women than men, the highest female-to-male ratio being recorded during the reproductive period. This evidence has led to the suggestion that female hormonal and reproductive factors may account for the observed DTC gender disparity. This review focuses on current evidence on the risk of DTC in conjunction with major female reproductive factors, including the impact of pregnancy on DTC occurrence and progression/recurrence. Overall, studies exploring the link between the risk of DTC and menstrual and menopausal factors, oral contraceptives and/or hormone replacement therapy, showed these associations, if any, to be generally weak. Nonetheless, there is some evidence that higher levels of exposure to estrogens during reproductive years may confer an increased risk of DTC. As far as pregnancy is concerned, it is unclear whether a potential association between parity and risk of DTC actually exists, and whether it is enhanced in the short-term following delivery. A possible role for pregnancy-related factors in DTC progression has been recently suggested by some reports, the results of which are consistent with a worse outcome in the short-term of women diagnosed with DTC during gestation compared to non-pregnant control patients. Also, some progression of disease has been described in women with structural evidence of disease prior to pregnancy. However, there seems to be no impact from pregnancy in DTC-related death or overall survival. Several in vitro and animal studies have evaluated the influence of estrogens (E) and estrogen receptors (ERs) on thyroid cell proliferation. Presently available data are indicative of a role of E and ERs in thyroid cancer growth, although considerable discrepancies in respect to ER expression patterns in thyroid cancer tissues actually exist. Further studies providing more direct evidence on the possible role of E and of placental hormones and growth factors on thyroid growth may expand our knowledge on the mechanisms beyond the gender disparity of proliferative thyroid diseases.

Clinicopathological Characteristics and Prognosis of Papillary Thyroid Carcinoma in Naturally Menopausal Women with Various Durations of Premenarche, Reproductive Periods, and Postmenopausal Stages

Background. Papillary thyroid cancer (PTC) exhibits a higher incidence in women. Due to various ages at menarche and menopause, estrogen levels vary, which may account for the differences in the occurrence, development, and prognosis of female patients with PTC. Objective. The aim of this study was to investigate the association between various durations in different estrogen levels and PTC and to provide important information to guide clinical management and treatment of this disease. Methods. First, we selected naturally menopausal female study subjects diagnosed with PTC at Zhejiang Cancer Hospital from 2007 to 2012 and then compared the differences in clinicopathological characteristics and prognosis among subjects with various lengths of premenarche, reproductive periods, and postmenopausal stages. Results. We found that all patients showed a significantly higher incidence of tumor multicentricity and intrathyroidal dissemination as the time after menopause increased. Additionally, women with shorter (<30) or longer (>38) reproductive lives had increased recurrence rates of PTC. Conclusions. In this study, we did not find any relationship of self-reported menarche and menopausal ages with the prognosis of PTC patients. More importantly, natural postmenopausal PTC patients with shorter or longer reproductive life, compared to the normal groups, had a higher rate of cancer recurrence and the patients with these characteristics could be recommended a more aggressive surgical treatment.

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.

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).

Maternal High Estradiol Exposure is Associated with Elevated Thyroxine and Pax8 in Mouse Offspring

Our previous studies have shown that maternal high estradiol (E₂) environment increased the risk of thyroid dysfunction in offspring. However, the mechanism involved remains unexplored. To evaluate the thyroid function of offspring after high E₂ exposure and to explore the underlying mechanism, we established a high E₂ mouse model of early pregnancy, and detected thyroid hormones of their offspring. In thyroids of offspring, the expressions of Tg, Nis, Tpo, Pax8, and Titf1 and CpG island methylation status of Pax8 and genes involved in methylation were analyzed. We found that thyroxine (T4) and FT4 levels of offspring were obviously increased in the high-E₂ group, especially in females. In both 3- and 8-week-old offspring of the high-E₂ group, Pax8 was significantly up-regulated in thyroid glands, accompanied by the abnormal CpG island methylation status in the promoter region. Furthermore, Dnmt3a and Mbd1 were obviously down-regulated in thyroids of the high E₂ group. Besides, the disturbance of thyroid function in females was more severe than that in males, implying that the effects were related to gender. In summary, our study indicated that maternal high E₂ exposure disturbed the thyroid function of offspring through the dysregulation and abnormal DNA methylation of Pax8.

Risk Factors for Thyroid Cancer: A Hospital-Based Case-Control Study in Korean Adults

PURPOSE

Although the incidence of thyroid cancer in Korea has rapidly increased over the past decade, few studies have investigated its risk factors. This study examined the risk factors for thyroid cancer in Korean adults.

MATERIALS AND METHODS

The study design was a hospital-based case-control study. Between August 2002 and December 2011, a total of 802 thyroid cancer cases out of 34,211 patients screened from the Cancer Screenee. Cohort of the National Cancer Center in South Korea were included in the analysis. A total of 802 control cases were selected from the same cohort, and matched individually (1:1) by age (±2 years) and area of residence for control group 1 and additionally by sex for control group 2.

RESULTS

Multivariate conditional logistic regression analysis using the control group 1 showed that females and those with a family history of thyroid cancer had an increased risk of thyroid cancer, whereas ever-smokers and those with a higher monthly household income had a decreased risk of thyroid cancer. On the other hand, the analysis using control group 2 showed that a family history of cancer and alcohol consumption were associated with a decreased risk of thyroid cancer, whereas higher body mass index (BMI) and family history of thyroid cancer were associated with an increased risk of thyroid cancer.

CONCLUSION

These findings suggest that females, those with a family history of thyroid cancer, those with a higher BMI, non-smokers, non-drinkers, and those with a lower monthly household income have an increased risk of developing thyroid cancer.

The Prevalence of Thyroid Nodules and an Analysis of Related Lifestyle Factors in Beijing Communities

Thyroid nodules (TNs) have annual increasing trends worldwide, and large-scale investigations on the prevalence of TNs in Beijing communities have not been conducted since the introduction of salt iodization in 1995. We performed a cross-sectional study to determine the prevalence of TNs, their epidemiological characteristics, and their correlation with lifestyle factors. A total of 6324 permanent residents aged 18 years or older (mean age, 52.15 ± 11.58 years) from seven representative communities in Beijing were included in the analyses. Once informed consent was obtained, the subjects were asked to complete questionnaires, a physical examination, and thyroid ultrasound. A total of 3100 cases had TNs. The overall prevalence rate was 49.0%, and the age-standardized prevalence was 40.1%, which increased significantly as age increased (p < 0.001). The prevalence was significantly higher in females compared to males (p < 0.001), and it was significantly higher among female current smokers and former smokers compared to non-smokers (p = 0.007). There was no correlation between alcohol consumption and TNs, and there were no significant differences in the prevalence among different groups of taste preference. The prevalence decreased with an increased frequency of seafood intake (p = 0.015) and with higher literacy levels (p < 0.001). The Cochran-Armitage trend test showed that the prevalence significantly increased with decreased physical labor and exercise intensity (p < 0.001, p = 0.009). Logistic regression analysis showed that age (Odds ratio (OR) = 1.039 (1.034-1.044), p < 0.001), the female sex (OR = 1.789 (1.527-2.097)), Body mass index (BMI) (OR = 1.019 (1.005-1.034)), and current smoking habits (OR = 1.246 (1.046-1.483)) were independent risk factors for TNs. Our findings indicate that there is a high prevalence of TNs in Beijing, with a higher prevalence in females than in males. Moreover, the prevalence increases as age increases. Smoking and BMI are independent risk factors for TNs. Therefore, intervention against smoking and weight loss might help reduce the risk of TN occurrence.

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.

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.

Progesterone Upregulates Gene Expression in Normal Human Thyroid Follicular Cells

Thyroid cancer and thyroid nodules are more prevalent in women than men, so female sex hormones may have an etiological role in these conditions. There are no data about direct effects of progesterone on thyroid cells, so the aim of the present study was to evaluate progesterone effects in the sodium-iodide symporter NIS, thyroglobulin TG, thyroperoxidase TPO, and KI-67 genes expression, in normal thyroid follicular cells, derived from human tissue. NIS, TG, TPO, and KI-67 mRNA expression increased significantly after TSH 20 μUI/mL, respectively: 2.08 times, P < 0.0001; 2.39 times, P = 0.01; 1.58 times, P = 0.0003; and 1.87 times, P < 0.0001. In thyroid cells treated with 20 μUI/mL TSH plus 10 nM progesterone, RNA expression of NIS, TG, and KI-67 genes increased, respectively: 1.78 times, P < 0.0001; 1.75 times, P = 0.037; and 1.95 times, P < 0.0001, and TPO mRNA expression also increased, though not significantly (1.77 times, P = 0.069). These effects were abolished by mifepristone, an antagonist of progesterone receptor, suggesting that genes involved in thyroid cell function and proliferation are upregulated by progesterone. This work provides evidence that progesterone has a direct effect on thyroid cells, upregulating genes involved in thyroid function and growth.

Decreased Expression of GPER1 Gene and Protein in Goiter

Goiter is more common in women, suggesting that estrogen could be involved in its physiopathology. The presence of classical estrogen receptors (ERα and ERβ) has been described in thyroid tissue, suggesting a direct effect of estrogen on the gland. A nonclassic estrogen receptor, the G-protein-coupled estrogen receptor (GPER1), has been described recently in several tissues. However, in goiter, the presence of this receptor has not been studied yet. We investigated GPER1 gene and protein expressions in normal thyroid and goiter using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot, respectively. In normal thyroid (n = 16) and goiter (n = 19), GPER1 gene was expressed in all samples, while GPER1 protein was expressed in all samples of normal thyroid (n = 15) but in only 72% of goiter samples (n = 13). When comparing GPER1 gene and protein levels in both conditions, gene expression and protein levels were higher in normal thyroid than in goiter, suggesting a role of this receptor in this condition. Further studies are needed to elucidate the role of GPER1 in normal thyroid and goiter.

Time trends and age-period-cohort analyses on incidence rates of thyroid cancer in Shanghai and Hong Kong

Background

Increasing incidence rates of thyroid cancer have been noted worldwide, while the underlying reasons remain unclear.

Methods

Using data from population-based cancer registries, we examined the time trends of thyroid cancer incidence in two largest cities in China, Shanghai and Hong Kong, during the periods 1973–2009 and 1983–2011, respectively. We further performed age-period-cohort analyses to address the possible underlying reasons for the observed temporal trends.

Results

We observed continuous increases in the incidence rates of thyroid cancer in Shanghai and Hong Kong, since the 1980s, in addition to higher incidence rates in the 1970s in both sexes in Shanghai. The age-standardized incidence rate of thyroid cancer increased by 3.1% [95% confidence interval (CI): 1.0%, 5.1%] and 3.8% (95% CI: 1.9%, 5.7%) per year on average, respectively, in Shanghai men and women during the period 1973–2009, while it increased by 2.2% (95% CI: 1.5%, 2.8%) and 2.7% (1.6%, 3.8%) per year on average, respectively, in Hong Kong men and women during the period 1983–2011. We observed global changes in trends across all age groups in similar ways, in addition to varied trends across different generations (birth cohorts).

Conclusions

The increased incidence rates of thyroid cancer in these two Chinese populations during recent decades may be contributable to a combination of the introduction of more sensitive diagnostic techniques and the increasing prevalence of environmental exposures in the populations.

Altered thyroid hormone profile in offspring after exposure to high estradiol environment during the first trimester of pregnancy: a cross-sectional study

BACKGROUND

The increasing number of babies conceived by in vitro fertilization and embryo transfer (IVF-ET) shifts concern from pregnancy outcomes to long-time health of offspring. Maternal high estradiol (E2) is a major characteristic of IVF-ET and lasts throughout the first trimester of pregnancy. The fetal thyroid develops during this period and may thus be affected by exposure to the supra-physiological E2. The aim of this study is to investigate whether the high E2 maternal environment in the first trimester increases the risk of thyroid dysfunction in children born following IVF-ET.

METHODS

A cross-sectional survey design was used to carry out face-to-face interviews with consecutive children attending the hospital. A total of 949 singletons born after fresh embryo transfer (ET) (n=357), frozen ET (n=212), and natural conception (NC) (n=380), aged 3 to 10 years old, were included. All children were thoroughly examined. Meanwhile, another 183 newborns, including 55 fresh ET, 48 frozen ET, and 80 NC were studied. Levels of serum T3, FT3, T4, FT4, and TSH and levels of maternal E2 at different stages of the first trimester were examined.

RESULTS

The mean serum E2 levels of women undergoing fresh ET during the first trimester of pregnancy were significantly higher than those of the women undergoing frozen ET or following NC. The thyroid hormone profile, especially the levels of T4, FT4, and TSH, were significantly increased in 3- to 10-year-old children conceived by fresh ET compared to NC. The same tendency was confirmed in newborns. However, levels of T4 and TSH in the frozen ET group were nearer to that of the NC group. Furthermore, levels of T4 and FT4 in fresh ET were positively correlated with maternal serum levels of E2 during early pregnancy.

CONCLUSIONS

The maternal high E2 environment in the first trimester is correlated with increased risk of thyroid dysfunction. Frozen ET could reduce risks of thyroid damage in children conceived by IVF. Further studies are needed to confirm these findings and to better determine the underlying molecular mechanisms and clinical significance.

TRIAL REGISTRATION

ChicCTR-OCC-14004682 (22-05-2014).

Obesity and the risk of papillary thyroid cancer: a pooled analysis of three case-control studies

BACKGROUND

There is a correlation between temporal trends of obesity prevalence and papillary thyroid cancer (PTC) incidence in the United States. Obesity is a well-recognized risk factor for many cancers, but there are few studies on the association between obesity and PTC risk. We investigated the association between anthropometric measurements and PTC risk using pooled individual data from three case-control populations.

METHODS

Height and weight information were obtained from three independent case-control studies, including 1917 patients with PTC (1360 women and 557 men) and 2127 cancer-free controls from the United States, Italy, and Germany. Body mass index (BMI), body fat percentage, and body surface area (BSA) were calculated. An unconditional logistic regression model was used to calculate odds ratios (ORs) and confidence intervals (CIs) with respect to risk of PTC, adjusted by age, sex, race/ethnicity, and study site.

RESULTS

In the pooled population, for both men and women, an increased risk of PTC was found to be associated with greater weight, BMI, body fat percentage, and BSA, whereas a reduced risk of PTC was associated with greater height, in the pooled population for both men and women. Compared with normal-weight subjects (BMI 18.5-24.9 kg/m2), the ORs for overweight (BMI 25-29.9 kg/m2) and obese (BMI≥30 kg/m2) subjects were 1.72 [CI 1.48-2.00] and 4.17 [CI 3.41-5.10] respectively. Compared with the lowest quartile of body fat percentage, the ORs for the highest quartile were 3.83 [CI 2.85-5.15] in women and 4.05 [CI 2.67-6.15] in men.

CONCLUSION

Anthropometric factors, especially BMI and body fat percentage, were significantly associated with increased risk of PTC. Future studies of anthropometric factors and PTC that incorporate intermediate factors, including adiposity and hormone biomarkers, are essential to help clarify potential mechanisms of the relationship.

The prognosis and treatment of primary thyroid cancer occurred in breast cancer patients: comparison with ordinary thyroid cancer

PURPOSE

Due to the increased prevalence of thyroid cancer, it has been frequently detected in breast cancer patients recently. The aim of this study was to evaluate the clinicopathologic characteristics of thyroid cancer in breast cancer patients with respect to prognosis and treatment.

METHODS

From August 1998 to September 2012, 101 breast cancer patients were diagnosed with thyroid cancer (BT group). One hundred ninety-three female patients with a thyroid malignancy that underwent thyroidectomy in 2008 were recruited as controls (oT group). The clinicopathologic results of these two groups were compared.

RESULTS

Patients were older (51.40 vs. 47.16, P < 0.001), mean tumor size was smaller (0.96 cm vs. 1.43 cm, P < 0.001), and extrathyroidal extension was less common in the BT group. In both groups, papillary thyroid carcinoma was the most common type of thyroid malignancy. T and N classifications of thyroid cancer were less severe in the BT group, but group TNM stages were similar. Endoscopic thyroid surgery was performed in 12.9% of patients in the BT group and in 6.7% of patients in the oT group. Postoperative radioactive iodine ablation was performed less often in the BT group (P < 0.001). Group recurrence rates were not significantly different.

CONCLUSION

Thyroid cancer in breast cancer patients was diagnosed at earlier status than ordinary thyroid cancer. However, the prognosis of thyroid cancer in breast cancer patients was not superior to that in patients with thyroid cancer alone. Radioactive iodine ablation was performed less often and endoscopic surgery could be performed in breast cancer patients.

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.

Validation of reference genes for normalizing gene expression in real-time quantitative reverse transcription PCR in human thyroid cells in primary culture treated with progesterone and estradiol

The use of appropriately chosen reference genes for normalizing gene expression in real-time quantitative reverse transcription polymerase chain reaction is an important step in the analysis of gene expression, compensating for several technical factors. As female sex hormones have been shown to influence growth and differentiation of thyroid follicular cells, the establishment of normalizer genes in human thyroid cells in primary culture, treated with progesterone, and estradiol, is important to evaluate their effect on gene expression in these cells, so candidate reference genes were studied. β-Actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β2-microglobulin (B2M), and TATA box binding protein (TBP) were evaluated in thyroid cells treated with estradiol, progesterone, and their inhibitors. Normfinder software was used to assess the stability of the genes and identified β-actin as the gene with adequate stability and lower inter-group variations, when compared to TBP, B2M, and GAPDH.