Thyroid hormones and breast cancer association according to menopausal status and body mass index

Investigating the clinical significance of immune and thyroid biomarkers in women with breast cancer and Hashimoto's thyroiditis

Breast cancer with Hashimoto's thyroiditis (BC-HT) presents a unique immuno-thyroid interplay that remains poorly understood. This study investigates the relationships between thyroid function markers (TSH, T3, T4), immune markers (CD33, CD44), and thyroid autoantibodies (Anti-TPO, Anti-Tg) in BC-HT patients and healthy controls. Normality testing confirmed non-parametric data distribution, necessitating Mann-Whitney U tests for group comparisons. BC-HT patients exhibited significantly elevated TSH, CD33, Anti-TPO, and Anti-Tg levels, alongside reduced T3 and T4, compared to controls, indicating thyroid dysfunction. Spearman's correlation analysis revealed strong negative correlations between TSH and T3/T4 in controls, which were lost in BC-HT, suggesting disruption of normal thyroid feedback mechanisms. Additionally, CD33 and CD44 correlations with thyroid hormones were evident in controls but absent in BC-HT, highlighting altered immune-thyroid interactions. ROC analysis demonstrated high diagnostic performance for TSH, Anti-Tg, and Anti-TPO, with sensitivities exceeding 0.75, whereas CD33 and CD44 showed limited diagnostic utility. These findings suggest a distinct immuno-thyroid dysregulation in BC-HT patients and highlight the potential of thyroid-specific markers for disease stratification. Future research should focus on longitudinal studies and mechanistic investigations to further delineate the role of immune markers in breast cancer pathophysiology within the context of thyroid autoimmunity.

Stress regulatory hormones and cancer: the contribution of epinephrine and cancer therapeutic value of beta blockers

The word "cancer" evokes myriad emotions, ranging from fear and despair to hope and determination. Cancer is aptly defined as a complex and multifaceted group of diseases that has unapologetically led to the loss of countless lives and affected innumerable families across the globe. The battle with cancer is not only a physical battle, but also an emotional, as well as a psychological skirmish for patients and for their loved ones. Cancer has been a part of our history, stories, and lives for centuries and has challenged the ingenuity of health and medical science, and the resilience of the human spirit. From the early days of surgery and radiation therapy to cutting-edge developments in chemotherapeutic agents, immunotherapy, and targeted treatments, the medical field continues to make significant headway in the fight against cancer. However, even after all these advancements, cancer is still among the leading cause of death globally. This urges us to understand the central hallmarks of neoplastic cells to identify novel molecular targets for the development of promising therapeutic approaches. Growing research suggests that stress mediators, including epinephrine, play a critical role in the development and progression of cancer by inducing neoplastic features through activating adrenergic receptors, particularly β-adrenoreceptors. Further, our experimental data has also shown that epinephrine mediates the growth of T-cell lymphoma by inducing proliferation, glycolysis, and apoptosis evasion via altering the expression levels of key regulators of these vital cellular processes. The beauty of receptor-based therapy lies in its precision and higher therapeutic value. Interestingly, the enhanced expression of β-adrenergic receptors (ADRBs), namely ADRB2 (β2-adrenoreceptor) and ADRB3 (β3-adrenoreceptor) has been noted in many cancers, such as breast, colon, gastric, pancreatic, and prostate and has been reported to play a pivotal role in facilitating cancer growth mainly by promoting proliferation, evasion of apoptosis, angiogenesis, invasion and metastasis, and chemoresistance. The present review article is an attempt to summarize the available findings which indicate a distinct relationship between stress hormones and cancer, with a special emphasis on epinephrine, considered as a key stress regulatory molecule. This article also discusses the possibility of using beta-blockers for cancer therapy.

Association between thyroid disorders and extra-thyroidal cancers, a review

Thyroid hormone has been shown to have both tumor-promoting and tumor-suppressing actions, which has led to significant debate over its involvement in the development of cancer. Proliferation, apoptosis, invasiveness, and angiogenesis are all aspects of cancer that are affected by the thyroid hormones T3 and T4, according to research conducted in animal models and in vitro experiments. The effects of thyroid hormones on cancer cells are mediated by many non-genomic mechanisms, one of which involves the activation of the plasma membrane receptor integrin αvβ3. Typically, abnormal amounts of thyroid hormones are linked to a higher occurrence of cancer. Both benign and malignant thyroid disorders were found to be associated with an increased risk of extra-thyroidal malignancies, specifically colon, breast, prostate, melanoma, and lung cancers. The purpose of this review was to shed light on this link to define which types of cancer are sensitive to thyroid hormones and, as a result, are anticipated to respond favorably to treatment of the thyroid hormone axis.

The crosstalk between benign thyroid disease and breast cancer: A single center study

This study aims to investigate the relationship between benign thyroid disease and breast cancer. The clinical study includes a total of 600 participants, divided into 2 groups: the control group (N = 300), which consists of individuals from the checkup population during the same periods, and the experimental group (N = 300), which consists of patients with breast cancer. General data of the participants, including age, tumor diameter, tumor staging, pathological classification, lymph node metastasis, and classification of benign thyroid disease, were collected and analyzed. The levels of TT3, TT4, FT3, FT4, TSH, TPOAb, and TgAb in blood samples from the experimental and control groups were determined using a radioimmune method. The levels of TPOAb, TgAb, and TSH in the experimental group were significantly higher than those in the control group, while the levels of TT3, TT4, FT3, and FT4 in the experimental group were significantly lower. The general data of the participants contributed to the appropriate sample size and allocation. Furthermore, benign thyroid disease contributes to the development of breast cancer by regulating the levels of TT3, TT4, FT3, FT4, TSH, TPOAb, and TgAb.

Deep learning in spatially resolved transcriptfomics: a comprehensive technical view

Spatially resolved transcriptomics (SRT) is a pioneering method for simultaneously studying morphological contexts and gene expression at single-cell precision. Data emerging from SRT are multifaceted, presenting researchers with intricate gene expression matrices, precise spatial details and comprehensive histology visuals. Such rich and intricate datasets, unfortunately, render many conventional methods like traditional machine learning and statistical models ineffective. The unique challenges posed by the specialized nature of SRT data have led the scientific community to explore more sophisticated analytical avenues. Recent trends indicate an increasing reliance on deep learning algorithms, especially in areas such as spatial clustering, identification of spatially variable genes and data alignment tasks. In this manuscript, we provide a rigorous critique of these advanced deep learning methodologies, probing into their merits, limitations and avenues for further refinement. Our in-depth analysis underscores that while the recent innovations in deep learning tailored for SRT have been promising, there remains a substantial potential for enhancement. A crucial area that demands attention is the development of models that can incorporate intricate biological nuances, such as phylogeny-aware processing or in-depth analysis of minuscule histology image segments. Furthermore, addressing challenges like the elimination of batch effects, perfecting data normalization techniques and countering the overdispersion and zero inflation patterns seen in gene expression is pivotal. To support the broader scientific community in their SRT endeavors, we have meticulously assembled a comprehensive directory of readily accessible SRT databases, hoping to serve as a foundation for future research initiatives.

Thyroid hormone enhances estrogen-mediated proliferation and cell cycle regulatory pathways in steroid receptor-positive breast Cancer

Estrogen receptor (ER) α expression and associated signaling is a major driver of over two-thirds of all breast cancers (BC). ER targeting strategies are typically used as a first-line therapy in patients with steroid receptor positive (SR+) disease. Secondary resistance to anti-estrogenic agents may occur with clonal expansion and disease progression. Mechanisms underlying hormone resistance are an expanding field of significant translational importance. Cross-talk with other nuclear hormones, receptors, and signaling pathways, including thyroid hormones (TH) and their receptors (THRs), have been shown to promote endocrine therapy resistance in some studies. We have shown that TH replacement therapy (THRT) was independently and significantly associated with higher rates of relapse and mortality in SR positive (+), node-negative (LN-) BC patients, whereas it showed no association with outcomes in SR negative (-) patients. LN-, SR+ patients receiving THRT and tamoxifen had the worst outcomes, suggesting a pro-carcinogenic interaction that significantly and independently shortened survival and increased mortality. Using in vivo and in vitro models, we previously showed hormonal cross-talk, altered gene signaling, target gene activation, and resistance to tamoxifen in the presence of TH. In this report, we show TH ± E2 ± tamoxifen inhibits cell cycle control signaling, reduces apoptosis, and enhances cell proliferation, tumor growth, tamoxifen resistance, and clonal expansion. Mechanistically these changes involve numerous genes and pathways, including critical cell cycle regulatory proteins and genes identified using various molecular methods. These studies facilitate a greater mechanistic understanding of the biological and molecular impact of TH on SR+ BC.

Anti-TPO antibody and thyroid hormone levels in Iranian female breast cancer patients and their association with prognostic factors: a case-control study

The aim of this study was to assess prevalence of anti-thyroid peroxidase (anti-TPO) antibody and thyroid hormones in Iranian female breast cancer patients, compare them to a control population, and investigate their association with prognostic factors. In this case-control study, breast cancer patients were selected from a surgery clinic in a tertiary hospital and control group participants were enrolled from those who had visited for mammography screening. Participants with any history of thyroid disease, or thyroid related medication were excluded from both groups. Groups were assessed for levels of thyroid stimulating hormone (TSH), T3, T4, and anti-TPO. In addition, the status of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2) was determined for cancer patients. Overall 69 participants (39 cancer patients and 30 controls) were included. Difference in serum anti-TPO levels between the two groups was not statistically significant (p-value: 0.184). While a significant difference was observed for T4 and TSH levels between groups (p-value: 0.034 and <0.001, respectively), T3 levels did not reveal any significant difference (p-value: 0.177). In addition, ER, PR, and HER2 status were not correlated with anti-TPO levels. This results can serve as preliminary evidence that thyroid autoimmunity is not correlated with breast cancer incidence in Iranian female population. However, additional studies with larger sample sizes are required for more conclusive evidence.

Links between Breast and Thyroid Cancer: Hormones, Genetic Susceptibility and Medical Interventions

Breast and thyroid glands are two common sites of female malignancies. Since the late 19th century, physicians have found that the cancers in either thyroid or mammary gland might increase the risk of second primary cancers in the other site. From then on, many observational clinical studies have confirmed the hypothesis and more than one theory has been developed to explain the phenomenon. Since the two glands both have secretory functions and are regulated by the hypothalamic-pituitary axis, they may share some common oncogenic molecular pathways. However, other risks factors, including medical interventions and hormones, are also observed to play a role. This article aims to provide a comprehensive review of the associations between the two cancers. The putative mechanisms, such as hormone alteration, autoimmune attack, genetic predisposition and other life-related factors are reviewed and discussed. Medical interventions, such as chemotherapy and radiotherapy, can also increase the risk of second primary cancers. This review will provide novel insights into the research designs, clinical managements and treatments of thyroid and breast cancer patients.

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

Thyroid Diseases and Breast Cancer

Epidemiological studies aimed at defining the association of thyroid diseases with extra-thyroidal malignancies (EM) have aroused considerable interest in the possibility of revealing common genetic and environmental factors underlying disease etiology and progression. Over the years, multiple lines of evidence indicated a significant relationship between thyroid carcinomas and other primary EM, especially breast cancer. For the latter, a prominent association was also found with benign thyroid diseases. In particular, a meta-analysis revealed an increased risk of breast cancer in patients with autoimmune thyroiditis, and our recent work demonstrated that the odds ratio (OR) for breast cancer was raised in both thyroid autoantibody-positive and -negative patients. However, the OR was significantly lower for thyroid autoantibody-positive patients compared to the negative ones. This is in agreement with findings showing that the development of thyroid autoimmunity in cancer patients receiving immunotherapy is associated with better outcome and supports clinical evidence that breast cancer patients with thyroid autoimmunity have longer disease-free interval and overall survival. These results seem to suggest that factors other than oncologic treatments may play a role in the initiation and progression of a second primary malignancy. The molecular links between thyroid autoimmunity and breast cancer remain, however, unidentified, and different hypotheses have been proposed. Here, we will review the epidemiological, clinical, and experimental data relating thyroid diseases and breast cancer, as well as the possible hormonal and molecular mechanisms underlying such associations.

Impact of Hypothyroidism on Patients with Hepatocellular Carcinoma Undergoing Liver Transplantation

BACKGROUND

This work endeavored to explore the effect of hypothyroidism on mortality in subjects with HCC who underwent living-donor liver transplantation (LDLT).

METHODS

This prospective study included 107 patients with HCC subjected to LDLT, divided into hypothyroid group (n=53) and euthyroid group (n=54). The primary objectives were overall and disease-free survival (DFS).

RESULTS

Euthyroid and hypothyroid groups were comparable in all baseline characteristics except the age of patients. Overall survival (OS) of the whole group at 48 months was 68.8%, while the DFS was 60.2%. On univariate analysis, OS was negatively affected by the older age of the patients (p<0.001) or the donor (p<0.001), hypothyroidism (p=0.008), HBV (p=0.029), larger tumor size (p=0.023), and defective Milan criteria (p=0.022). On multivariate analysis, the age of the patients and donors was the independent factor affecting OS. On univariate analysis, DFS was negatively affected by older age of the patients (p < 0.001) or the donor (p=0.005), hypothyroidism (p=0.005), HBV (p=0.019), larger tumor size (p=0.023), and defective Milan criteria (p=0.020). On multivariate analysis, the age of the patients, thyroid status, and Milan criteria were the independent factors affecting DFS.

CONCLUSION

Hypothyroidism is a risk factor for worse outcomes in HCC patients after liver transplantation.

Thyroid dysfunction and breast cancer risk among women in the UK Biobank cohort

This study aimed to evaluate the association between thyroid dysfunction and breast cancer risk. We included 239,436 females of the UK Biobank cohort. Information on thyroid dysfunction, personal and family medical history, medications, reproductive factors, lifestyle, and socioeconomic characteristics was retrieved from baseline self-reported data and hospital inpatient databases. Breast cancer diagnoses were identified through population-based registries. We computed Cox models to estimate hazard ratios (HRs) of breast cancer incidence for thyroid dysfunction diagnosis and treatments, and examined potential confounding and effect modification by comorbidities and breast cancer risk factors. In our study, 3,227 (1.3%) and 20,762 (8.7%) women had hyper- and hypothyroidism prior to the baseline. During a median follow-up of 7.1 years, 5,326 (2.2%) women developed breast cancer. Compared to no thyroid dysfunction, there was no association between hypothyroidism and breast cancer risk overall (HR = 0.93, 95% confidence interval (CI): 0.84-1.02, 442 cases), but we found a decreased risk more than 10 years after hypothyroidism diagnosis (HR=0.85, 95%CI 0.74-0.97, 226 cases). There was no association with hyperthyroidism overall (HR=1.08, 95%CI 0.86-1.35, 79 cases) but breast cancer risk was elevated among women with treated hyperthyroidism (HR=1.38, 95%CI: 1.03-1.86, 44 cases) or aged 60 years or more at hyperthyroidism diagnosis (HR=1.74, 95%CI: 1.01-3.00, 113 cases), and 5-10 years after hyperthyroidism diagnosis (HR=1.58, 95%CI: 1.06-2.33, 25 cases). In conclusion, breast cancer risk was reduced long after hypothyroidism diagnosis, but increased among women with treated hyperthyroidism. Future studies are needed to determine whether the higher breast cancer risk observed among treated hyperthyroidism could be explained by hyperthyroidism severity, type of treatment or aetiology.

Thyroglobulin as a negative marker for malignancy in canine and human breast tumors

Canine mammary gland tumors (CMTs) are the most common tumor type in female dogs. This study evaluated the expression pattern and role of thyroglobulin (Tg) in CMT and in human breast cancer (HBC). CMT samples were subjected to fine-needle aspiration, primary cell culture, and histopathology. The expression level of Tg was higher in benign CMT than in malignant CMT (mCMT) primary cells, particularly in the epithelial lineage. Moreover, treatment with Tg enhanced the sensitivity of doxorubicin in mCMT epithelial cells and mitigated proinflammatory response by increasing nuclear factor erythroid 2-related factor 2 (Nrf2). The proximal region of the Tg promoter was hypermethylated in mCMT epithelial cells, silencing Tg expression with concurrent downregulation of Nrf2-mediated antioxidant signaling. An identical pattern of Tg expression was observed in cytological and tissue samples. Tissue microarray analysis showed that Tg was highly expressed in normal and benign tissues when compared with their malignant counterparts, which was diminished along with higher histological grades. The survival rate was significantly higher in HBC patients with high Tg expression than those with low Tg expression. This study also showed that the progression of HBC is accompanied by the reduction of Tg expression along with augmentation of proinflammatory signaling. Our data suggested that Tg could be a negative indicator of malignancy in canine and human breast neoplasia.

Exogenous Thyroid Hormone Is Associated with Shortened Survival and Upregulation of High-Risk Gene Expression Profiles in Steroid Receptor-Positive Breast Cancers

PURPOSE

Thyroid disease is a frequent comorbidity in women with breast cancer, and many require thyroid hormone replacement therapy (THRT). We postulated that THRT has a deleterious clinical effect mechanistically through hormonal interactions, nuclear receptor cross-talk, and upregulation of high-risk breast cancer genes.

EXPERIMENTAL DESIGN

Observational studies of patients with lymph node-negative (LN-) breast cancer (n = 820 and n = 160) were performed to test interactions between THRT and clinical, histologic, outcome, and treatment variables. Differences between the two cohorts include but are not limited to patient numbers, decades of treatment, duration of follow-up/treatment, tumor sizes, incidence, and type and dose/regimen of antihormonal and/or chemotherapeutic agents. In vivo and vitro models, in silico databases, and molecular methods were used to study interactions and define mechanisms underlying THRT effects.

RESULTS

THRT significantly and independently reduced disease-free and breast cancer-specific overall survival of only the steroid receptor (SR)-positive (as compared with SR-negative) node-negative patients in both long-term observational studies. Patients with SR+ LN- breast cancer who received THRT and tamoxifen experienced the shortest survival of all treatment groups. A less potent interaction between THRT and aromatase inhibitors was noted in the second patient cohort. Using in vivo and in vitro models, TH administration enhanced estrogen and TH-associated gene expression and proliferation, nuclear colocalization of estrogen receptor and thyroid hormone receptor, and activation of genes used clinically to predict tumor aggression in SR+ breast cancer, including the IGF-IR, WNT, and TGFβ pathways.

CONCLUSIONS

We show clinically significant adverse interactions between THRT, estrogenic, and oncogenic signaling in patients with SR+ LN- breast cancer.

Causal associations of thyroid function and dysfunction with overall, breast and thyroid cancer: A two-sample Mendelian randomization study

Whether thyroid dysfunction plays a causal role in the development of cancer remains inconclusive. We conducted a two-sample Mendelian randomization study to investigate the associations between genetic predisposition to thyroid dysfunction and 22 site-specific cancers. Single-nucleotide polymorphisms associated with four traits of thyroid function were selected from a genome-wide association meta-analysis with up to 72,167 European-descent individuals. Summary-level data for breast cancer and 21 other cancers were extracted from the Breast Cancer Association Consortium (122,977 breast cancer cases and 105,974 controls) and UK Biobank (367,643 individuals). For breast cancer, a meta-analysis was performed using data from both sources. Genetically predicted thyroid dysfunction was associated with breast cancer, with similar patterns of associations in the Breast Cancer Association Consortium and UK Biobank. The combined odds ratios of breast cancer were 0.94 (0.91-0.98; p = 0.007) per genetically predicted one standard deviation increase in TSH levels, 0.96 (0.91-1.00; p = 0.053) for genetic predisposition to hypothyroidism, 1.04 (1.01-1.07; p = 0.005) for genetic predisposition to hyperthyroidism and 1.07 (1.02-1.12; p = 0.003) per genetically predicted one standard deviation increase in free thyroxine levels. Genetically predicted TSH levels and hypothyroidism were inversely with thyroid cancer; the odds ratios were 0.47 (0.30-0.73; p = 0.001) and 0.70 (0.51-0.98; p = 0.038), respectively. Our study provides evidence of a causal association between thyroid dysfunction and breast cancer (mainly ER-positive tumors) risk. The role of TSH and hypothyroidism for thyroid cancer and the associations between thyroid dysfunction and other cancers need further exploration.

Hyperthyroidism is associated with breast cancer risk and mammographic and genetic risk predictors

BACKGROUND

Despite the biological link between thyroid hormones and breast cancer cell proliferation shown in experimental studies, little is known about the association between hyperthyroidism and breast cancer, as well as its association with the most common mammographic and genetic risk predictors for breast cancer.

METHODS

This study estimates the incidence rate ratios (IRRs) of breast cancer among women diagnosed with hyperthyroidism, compared to those who are not, using two cohorts: a Swedish national cohort of the general female population (n = 3,793,492, 2002-2011) and the Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA, n = 69,598, 2002-2017). We used logistic regression to estimate the odds ratios (ORs) of hyperthyroidism according to the mammographic and genetic risk predictors for breast cancer.

RESULTS

An increased risk of breast cancer was observed in patients in the national cohort with hyperthyroidism (IRR = 1.23, 95% CI = 1.12-1.36), particularly for toxic nodular goiter (IRR = 1.38, 95% CI = 1.16-1.63). Hyperthyroidism was associated with higher body mass index, early age at first birth, and lower breastfeeding duration. Higher mammographic density was observed in women with toxic nodular goiter, compared to women without hyperthyroidism. Additionally, among genotyped women without breast cancer in the KARMA cohort (N = 11,991), hyperthyroidism was associated with a high polygenic risk score (PRS) for breast cancer overall (OR = 1.98, 95% CI = 1.09-3.60) and for estrogen receptor-positive specific PRS (OR = 1.90, 95% CI = 1.04-3.43).

CONCLUSION

Hyperthyroidism is associated with an increased risk of breast cancer, particularly for patients with toxic nodular goiter. The association could be explained by higher mammographic density among these women, as well as pleiotropic genetic variants determining shared hormonal/endocrine factors leading to the pathology of both diseases.

Thyroid Hormone in Hepatocellular Carcinoma: Cancer Risk, Growth Regulation, and Anticancer Drug Resistance

Thyroid hormone (TH) and its receptor (TR) are involved in differentiation, metabolic process, and growth regulation in hepatocellular carcinoma (HCC). The TH/TR complexes are ligand-dependent transcriptional factors, functioning through binding to thyroid hormone response elements (TREs) upstream of the target genes. To date, deciphering the biological effects of TH in cancer progression remains challenging. Several lines of evidence suggest a growth inhibitory effect of TH in liver cancer. Mutation and aberrant expression of TRs are highly correlated with several types of cancers including HCC. Several reports show that TH inhibits cell growth in liver cancer through regulation of cell-cycle-related genes and non-coding RNAs. A case–control study indicates that hypothyroidism is associated with an increased risk of HCC. Moreover, TH/TR suppresses hepatocarcinogenesis via selective autophagy. Conversely, other groups have indicated that TH promotes cancer cell proliferation. In vitro and in vivo experiments show that TH/TR enhances cancer cell migration and invasion, anticancer drug resistance, angiogenesis, and cancer stem cell self-renewal. Adding to the complexity of this issue, non-genomic effects of TH mediated by integrin receptor on cell surface can also modulate several biological functions. Accumulating evidence indicate that regulations by genomic and non-genomic effects of TH overlap. Taken together, these observations suggest that the functions of TH depend largely on cell context, and TH/TR plays a duel role in cancer progression. Therefore, understanding the maze of biological effects of TH has become a necessity when attempting to develop effective therapeutic and preventive strategies in liver cancer.

Association between thyroid gland diseases and breast cancer: a case-control study

BACKGROUND

At the present time, there is no consensus on the association between benign thyroid diseases and breast cancer (BC). Therefore, the aim of this study is to help shed some light on the association between hyperthyroidism, hypothyroidism, and thyroiditis and breast cancer risk.

METHODS

Use of the Disease Analyzer database (IQVIA) enabled us to perform a retrospective case-control study of 7408 women aged between 18 and 80, who were treated for an initial breast cancer diagnosis in a general practice in the United Kingdom between 2006 and 2015 (index date). Patients with a previous cancer diagnosis and an observation time of less than 12 months prior to the index date were excluded. The control group consisted of 7408 healthy women, who were matched to cases 1:1 by age, body mass index, hormone replacement therapy, and physician. The main outcome parameters of this study were the presence of thyroid disease (hypothyroidism, hyperthyroidism, struma, and thyroiditis) and the TSH values in the two groups. A univariate logistic regression model was used to investigate the association between benign thyroid diseases, TSH values, and BC.

RESULTS

The mean age was 58.4 years in both groups. We found a significant association between thyroiditis and BC (OR: 1.91, p = 0.01) and were able to refute the association between hyperthyroidism/hypothyroidism and BC. We also found that thyroid-stimulating hormone (TSH) had no significant effect on breast cancer risk.

CONCLUSION

Many experimental studies suggest a link between hyperthyroidism/hypothyroidism and BC. We were able to demonstrate an epidemiological association between thyroiditis and an increased BC risk. This shows the need for close monitoring for BC in women with thyroiditis.

Levothyroxine treatment is associated with an increased relative risk of overall and organ specific incident cancers - a cohort study of the Swedish population

High thyroid hormone values have been associated with an increased risk of incident cancers, especially breast cancer but also lung cancer and any solid cancers. We explored whether there is an increased risk of overall and cause-specific cancers in those receiving levothyroxine treatment. We included all individuals ≥ 18 years in Sweden (N = 8,573,313) on January 1 2009, and identified patients with two or more dispensed prescriptions of levothyroxine 2005-2006 (n = 253,193, 3.0 %). A cancer diagnosis in the Swedish Cancer Register 2009-2015 was used as outcome. We excluded patients with a cancer diagnosis before 2005. Cox regression was used (hazard ratios, HRs, and 95 % confidence intervals, CI) with adjustments for age, socioeconomic/neighborhood factors and co-morbidities. Totally 399,751 cases of incident cancer were identified, with a slight increased overall risk associated with levothyroxine treatment for both men, adjusted HR 1.06 (95 % CI 1.03-1.10), and women, adjusted HR 1.08 (95 % CI 1.07-1.10). For men, increased risks were found for cancers of the thyroid gland and other endocrine glands. For women, increased risks were found for cancers of the breast, endometrium, other female genitals (ovaries not included), stomach, colon, liver, pancreas, urinary bladder, skin, leukemia, and unspecified primary tumor. Unlike men, for women, no increased risk was found for cancer of the thyroid gland. In conclusions, levothyroxine treatment was associated with an excess cancer risk, including many different types of cancer, especially among women. Our results need confirmation by other studies, but levothyroxine is recommended to be prescribed only on approved indications.

Tetrac as an anti-angiogenic agent in cancer

The thyroid hormones T3 and T4 have emerged as pro-angiogenic hormones with important implications for cancer management. Endogenous circulating hormone levels may help stimulate cancer progression and limit the effectiveness of anticancer therapy, though clinical data remain inconclusive. The capacity of thyroid hormones to modulate angiogenesis is mediated through non-canonical mechanisms initiated at the cell surface receptor integrin αvβ3. This integrin is predominantly expressed on tumour cells, proliferating endothelial cells and tumour stroma-associated cells, emphasising its potential relevance in angiogenesis and tumour biology. Thyroid hormone/integrin αvβ3 signalling results in the activation of intracellular pathways that are commonly associated with angiogenesis and are mediated through classical pro-angiogenic molecules such as vascular endothelial growth factor. The naturally occurring T4 analogue tetrac blocks the pro-angiogenic actions of thyroid hormones at the integrin receptor, in addition to agonist-independent anti-angiogenic effects. Tetrac reduces endothelial cell proliferation, migration and tube formation through a reduction in the transcription of vascular growth factors/growth factor receptors, hypoxia-inducible factor-1α, pro-angiogenic cytokines and a number of other pro-angiogenic genes, while at the same time stimulating the expression of endogenous angiogenesis inhibitors. It further modulates vascular growth factor activity by disrupting the crosstalk between integrin αvβ3 and adjacent growth factor receptors. Moreover, tetrac disrupts thyroid hormone-stimulated tumour recruitment, differentiation and the pro-angiogenic signalling of tumour stroma-associated mesenchymal stem cells. Tetrac affects tumour-associated angiogenesis via multiple mechanisms and interferes with other cancer cell survival pathways. In conjunction with its low toxicity and high tissue selectivity, tetrac is a promising candidate for clinical application.

Nuclear Receptors Are Differentially Expressed and Activated in KAIMRC1 Compared to MCF7 and MDA-MB231 Breast Cancer Cells

We recently established a KAIMRC1 cell line that has unique features compared to the known breast cancer cell lines, MCF7 and MDA-MB231. To characterize it further, we investigated the expression profile of nuclear receptors and their respective co-factors in these cell lines. We confirm that in contrast to the triple negative cell line MDA-MB231, the MCF7 and KAIMRC1 are estrogen receptor alpha (ERa) and progesterone receptor alpha (PRa) positive, with significant lower expression of these receptors in KAIMRC1. KAIMRC1 cell is a vitamin D receptor (VDR) negative and V-ErbA-Related Protein 2 (EAR2) positive in contrast to MCF7 and MDA-MB231. Remarkably, the histone deacetylases (HDACs) are highly expressed in KAIRMC1 with HDAC6 and HDAC 7 are exclusively expressed in KAIMRC1 while thyroid hormone receptor-associated protein 80 (TRAP80), telomeric DNA binding protein 1 (TBP1) and TGF-beta receptor interacting protein (TRIP1) are absent in KAIMRC1 but present in MCF7 and MDA-MB231. In a luciferase reporter assay, the ERa coexpression is needed for estrogen receptor element (ERE)-luciferase activation by estradiol in KAIMRC1 but not in MCF7. The co-expression of exogenous Liver X receptor alpha (LXRa)/retinoid X receptor alpha (RXRa) are necessary for LXR responsive element (LXRE) activation by the GW3696 in the three cell lines. However, the activity of peroxisome proliferator-activated receptor response element (PPARE)-tk-luciferase reporter increased when peroxisome proliferator-activated receptors alpha (PPARa)/RXRa were coexpressed but the addition of PPARa agonist (GW7647) did not stimulate further the reporter. The signal of the PPARE reporter increased in a dose-dependent manner with rosiglitazone (PPARg agonist) in KAIMRC1, MCF7, and MDA-MB231 when the proliferator-activated receptors gamma (PPARg)/RXRa receptors were cotransfected. Retinoic acid-induced activation of retinoic acid receptor response element (RARE)-tk-luciferase is dependent on exogenous expression of retinoic acid receptor alpha (RARa)/RXRa heterodimer in MDA-MB 231 but not in MCF7 and KAIMRC1 cell lines. In the three cell lines, Bexarotene-induced retinoid X receptor response element (RXRE)-luciferase reporter activation was induced only if the RXRa/LXRa heterodimer were co-expressed. The vitamin D receptor response element (VDRE)-luciferase reporter activity showed another distinct feature of KAIMRC1, where only co-expression of exogenous vitamin D receptor (VDR)/RXRa heterodimer was sufficient to reach the maximum rate of activation of VDRE reporter. In the proliferation assay, nuclear receptors ligands showed a distinct effect on KAIMRC1 compared to MCF7 and MDA-MB231. Growth inhibition effects of used ligands suggest that KAIMRC1 correlate more closely to MDA-MB231 than MCF7. Vitamin D3, rosiglitazone, novel RXR compound (RXRc) and PPARa compound (GW6471) have the most profound effects. In conclusion, we showed that nuclear receptors are differentially expressed, activated and also their ligand produced distinct effects in KAIMRC1 compared to MCF7 and MDA-MB231. This finding gives us confidence that KAIMRC1 has a unique biological phenotype.

Serum concentration of thyroid hormones in abnormal and euthyroid ranges and breast cancer risk: A cohort study

The impact of variations in serum thyroid hormone concentration within the euthyroid range on breast cancer risk remains unclear. We investigated the effect of serum thyrotropin (TSH) and thyroid hormone concentration on breast cancer risk. This cohort study involved 62,546 Korean women, aged ≥40 years, who were free of breast cancer at baseline and underwent health examination with determination of free thyroxine (FT4) and TSH. A parametric proportional hazard model was used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI). During a median follow-up of 4.8 years (interquartile range: 2.8-7.3 years), 834 incident breast cancers were identified. Compared to normal FT4 level, abnormally high serum FT4 level was associated with an increased risk of incident breast cancer with a corresponding multivariable aHR (95% CI) of 1.98 (1.02-3.83). This association tended to be stronger in postmenopausal women than in premenopausal women. Within the euthyroid range, the highest TSH tertile was associated with a lower risk of breast cancer than the lowest TSH tertile with a corresponding aHR (95% CI) of 0.68 (0.55-0.84). In contrast, highest FT4 tertile was associated with a higher risk of breast cancer than the lowest FT4 tertile. Abnormally high FT4 as well as higher FT4 within the euthyroid range were positively associated with breast cancer risk, while higher TSH concentration within the euthyroid range was negatively associated with breast cancer risk. Our findings indicate that thyroid function within both the abnormal and euthyroid ranges may contribute to the development of breast cancer.

Thyroid Hormones and Cancer: A Comprehensive Review of Preclinical and Clinical Studies

Thyroid hormones take major part in normal growth, development and metabolism. Over a century of research has supported a relationship between thyroid hormones and the pathophysiology of various cancer types. In vitro studies as well as research in animal models demonstrated an effect of the thyroid hormones T3 and T4 on cancer proliferation, apoptosis, invasiveness and angiogenesis. Thyroid hormones mediate their effects on the cancer cell through several non-genomic pathways including activation of the plasma membrane receptor integrin αvβ3. Furthermore, cancer development and progression are affected by dysregulation of local bioavailability of thyroid hormones. Case-control and population-based studies provide conflicting results regarding the association between thyroid hormones and cancer. However, a large body of evidence suggests that subclinical and clinical hyperthyroidism increase the risk of several solid malignancies while hypothyroidism may reduce aggressiveness or delay the onset of cancer. Additional support is provided from studies in which dysregulation of the thyroid hormone axis secondary to cancer treatment or thyroid hormone supplementation was shown to affect cancer outcomes. Recent preclinical and clinical studies in various cancer types have further shown promising outcomes following chemical reduction of thyroid hormones or inhibition or their binding to the integrin receptor. This review provides a comprehensive overview of the preclinical and clinical research conducted so far.