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Thyroid Diseases and Breast Cancer. J Pers Med 2022; 12:jpm12020156. [PMID: 35207645 PMCID: PMC8876618 DOI: 10.3390/jpm12020156] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 01/27/2023] Open
Abstract
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.
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Wändell P, Carlsson AC, Li X, Sundquist J, Sundquist K. Levothyroxine treatment is associated with an increased relative risk of overall and organ specific incident cancers - a cohort study of the Swedish population. Cancer Epidemiol 2020; 66:101707. [PMID: 32222650 DOI: 10.1016/j.canep.2020.101707] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/09/2020] [Accepted: 03/15/2020] [Indexed: 12/24/2022]
Abstract
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.
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Affiliation(s)
- Per Wändell
- Division of Family Medicine and Primary Care, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.
| | - Axel C Carlsson
- Division of Family Medicine and Primary Care, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden; Academic Primary Health Care Centre, Stockholm Region, Stockholm, Sweden
| | - Xinjun Li
- Center for Primary Health Care Research, Lund University, Malmö, Sweden
| | - Jan Sundquist
- Center for Primary Health Care Research, Lund University, Malmö, Sweden; Department of Family Medicine and Community Health, Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, USA; Center for Community-Based Healthcare Research and Education (CoHRE), Department of Functional Pathology, School of Medicine, Shimane University, Japan
| | - Kristina Sundquist
- Center for Primary Health Care Research, Lund University, Malmö, Sweden; Department of Family Medicine and Community Health, Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, USA; Center for Community-Based Healthcare Research and Education (CoHRE), Department of Functional Pathology, School of Medicine, Shimane University, Japan
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Goemann IM, Marczyk VR, Romitti M, Wajner SM, Maia AL. Current concepts and challenges to unravel the role of iodothyronine deiodinases in human neoplasias. Endocr Relat Cancer 2018; 25:R625-R645. [PMID: 30400023 DOI: 10.1530/erc-18-0097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/10/2018] [Indexed: 12/20/2022]
Abstract
Thyroid hormones (THs) are essential for the regulation of several metabolic processes and the energy consumption of the organism. Their action is exerted primarily through interaction with nuclear receptors controlling the transcription of thyroid hormone-responsive genes. Proper regulation of TH levels in different tissues is extremely important for the equilibrium between normal cellular proliferation and differentiation. The iodothyronine deiodinases types 1, 2 and 3 are key enzymes that perform activation and inactivation of THs, thus controlling TH homeostasis in a cell-specific manner. As THs seem to exert their effects in all hallmarks of the neoplastic process, dysregulation of deiodinases in the tumoral context can be critical to the neoplastic development. Here, we aim at reviewing the deiodinases expression in different neoplasias and exploit the mechanisms by which they play an essential role in human carcinogenesis. TH modulation by deiodinases and other classical pathways may represent important targets with the potential to oppose the neoplastic process.
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Affiliation(s)
- Iuri Martin Goemann
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Vicente Rodrigues Marczyk
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Mirian Romitti
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, Brussels, Belgium
| | - Simone Magagnin Wajner
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Ana Luiza Maia
- Thyroid Unit, Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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Choi JH, Lee J, Yang S, Lee EK, Hwangbo Y, Kim J. Genetic variations in TAS2R3 and TAS2R4 bitterness receptors modify papillary carcinoma risk and thyroid function in Korean females. Sci Rep 2018; 8:15004. [PMID: 30301923 PMCID: PMC6177438 DOI: 10.1038/s41598-018-33338-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 09/25/2018] [Indexed: 12/31/2022] Open
Abstract
Type 2 taste receptors (T2Rs, TAS2Rs) mediate bitterness perception and are involved in diverse defence mechanisms in extraoral tissues. The thyrocyte-expressed T2Rs control thyroid hormone production, and this regulatory role may be associated with susceptibility to thyroid diseases. This study examined whether the variations in TAS2Rs modify the risk of papillary thyroid carcinoma (PTC) and whether such T2R-related PTC risk is associated with genetically modified thyroid function. We conducted a case-control study with 763 Korean females, including 250 PTC cases. Seventy-three single-nucleotide polymorphisms in 13 TAS2R genes and the pre-diagnosis levels of 4 thyroid-related functional markers [total triiodothyronine (TT3), free thyroxine, thyroid-stimulating hormone and thyroglobulin] were analysed. Individuals with TAS2R3/4 CC haplotype (rs2270009 and rs2234001) were at a lower risk for PTC than those with the remaining haplotypes (odds ratio = 0.59, 95% confidence interval: 0.36-0.97). Furthermore, TT3 levels were significantly reduced for TAS2R3/4 CC haplotype carriers compared with other haplotype carriers (p = 0.005). No other genetic variants exhibited critical associations with the PTC phenotype and biomarkers. In summary, genetic variations in T2R3/4 bitterness receptors may modify the PTC risk, and the genetically modified thyroid hormone level by those variations may be linked with the PTC-T2Rs association.
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Affiliation(s)
- Jeong-Hwa Choi
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Korea.,Department of Food Science and Nutrition, Keimyung University, 1095, Dalgubeol-daero, Dalseo-gu, Daegu, 42601, Korea
| | - Jeonghee Lee
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Korea
| | - Sarah Yang
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Korea.,Complex Disease & Genome Epidemiology Branch, Department of Epidemiology, School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Eun Kyung Lee
- Center for Thyroid Cancer, National Cancer Center Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Korea
| | - Yul Hwangbo
- Center for Thyroid Cancer, National Cancer Center Hospital, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Korea
| | - Jeongseon Kim
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Korea.
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Thyroid hormone receptor beta-1 expression in early breast cancer: a validation study. Breast Cancer Res Treat 2018; 171:709-717. [DOI: 10.1007/s10549-018-4844-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 05/29/2018] [Indexed: 12/19/2022]
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Peng X, Zhang Y, Sun Y, Wang L, Song W, Li Q, Zhao R. Overexpressing modified human TRβ1 suppresses the proliferation of breast cancer MDA-MB-468 cells. Oncol Lett 2018; 16:785-792. [PMID: 29963146 PMCID: PMC6019938 DOI: 10.3892/ol.2018.8764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 04/04/2018] [Indexed: 12/31/2022] Open
Abstract
A number of studies have indicated that thyroid hormone receptor β1 (TRβ1) functions as a tumor suppressor. TRs mediate transcriptional responses through a highly conserved DNA-binding domain (DBD). A novel rat TRβ isoform (rTRβΔ) was previously identified, in which a novel exon, N (108 bp), is located between exons 3 and 4 within the DBD; this exon represents the only difference between rTRβΔ and rTRβ1. In vitro, rTRβΔ exhibits a stronger tumor-suppressive capacity than rTRβ1, and further analysis revealed a high level of conservation between the rat and human DBD sequences. In the present study, an artificially modified human TRβ1 (m-hTRβ1) was constructed via the introduction of the 108-bp sequence into the corresponding position of the wild-type human TRβ1 (wt-hTRβ1) DBD. An electrophoretic mobility shift assay and transfection experiments confirmed that m-hTRβ1 is functional. Overexpression of m-hTRβ1 inhibits the proliferation of MDA-MB-468 cells in the presence of triiodothyronine by promoting apoptosis, which may be associated with the upregulation of Caspase-3 and Bak gene expression and the activation of the Caspase-3 protein. In addition, the pro-apoptotic effect of m-hTRβ1 was stronger, compared with wt-hTRβ1. These results indicated that m-hTRβ1 may act as a tumor suppressor in MDA-MB-468 cells. These data provided a novel insight into gene therapy for breast cancer.
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Affiliation(s)
- Xiaoxiang Peng
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Yangyang Zhang
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Yanli Sun
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Lujuan Wang
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Wei Song
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Qian Li
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
| | - Ronglan Zhao
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong 261053, P.R. China.,Department of Clinical Laboratory, Key Discipline of Clinical Laboratory Medicine of Shandong, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261053, P.R. China
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Cordel E, Reix N, Molière S, Mathelin C. [Hyperthyroidism and breast cancer: Is there a link?]. ACTA ACUST UNITED AC 2018; 46:403-413. [PMID: 29478847 DOI: 10.1016/j.gofs.2018.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Indexed: 12/23/2022]
Abstract
The objective of this review was to determine whether there is an association between hyperthyroidism and the risk of developing a breast cancer from the analysis of data in the literature. METHOD The analyzed articles were extracted from the PUBMED database from 2002 to 2017 using the following keywords "hyperthyroidism AND breast cancer" and "thyroid AND breast cancer". RESULTS A total of 22 studies were selected, including 8 cohort studies, 12 case-control studies and 2 meta-analyzes. Of these 22 studies, 15 have established a significant epidemiological or biological link between hyperthyroidism and breast cancer. Five of them were particularly interested in Graves' disease, and four demonstrated a positive association between this disease and the onset of breast cancer, especially within three years from the thyropathy diagnosis. These different studies also highlighted the increased risk of breast cancer seen in overweight or postmenopausal women. Contradictions persist over the types of mammary cancers observed and their prognosis. CONCLUSION This review reveals that women with hyperthyroidism appear to have a moderately high risk of breast cancer (RR<2). These data are corroborated by solid physiopathological hypotheses. Regardless of the type of thyropathy responsible for hyperthyroidism, care should be taken to ensure that these patients receive a clinical examination of the breasts on an annual basis and mammographic screening every 2 years from the age of 50 years.
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Affiliation(s)
- E Cordel
- Unité de sénologie, hôpital de Hautepierre, hôpitaux universitaires de Strasbourg, CHRU, 1, avenue Molière, 67098 Strasbourg cedex 09, France
| | - N Reix
- Laboratoire de biochimie et biologie moléculaire, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67091 Strasbourg, France; ICube UMR 7357, fédération de médecine translationnelle de Strasbourg (FMTS), université de Strasbourg/CNRS, IMIS, 4 rue Kirschleger, 67085 Strasbourg, France
| | - S Molière
- Unité d'imagerie de la femme, hôpital de Hautepierre, hôpitaux universitaires de Strasbourg, CHRU, 1, avenue Molière, 67098 Strasbourg cedex 09, France
| | - C Mathelin
- Unité de sénologie, hôpital de Hautepierre, hôpitaux universitaires de Strasbourg, CHRU, 1, avenue Molière, 67098 Strasbourg cedex 09, France; IGBMC, institut de génétique et de biologie moléculaire et cellulaire, Biologie du Cancer, 1, rue Laurent-Fries, 67400 Illkirch-Graffenstaden, France.
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Leese GP, Soto-Pedre E, Donnelly LA. Liothyronine use in a 17 year observational population-based study - the tears study. Clin Endocrinol (Oxf) 2016; 85:918-925. [PMID: 26940864 DOI: 10.1111/cen.13052] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/20/2016] [Accepted: 03/02/2016] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To look at adverse outcomes for patients on liothyronine compared to l-thyroxine. Some trials have examined the relative merits of liothyronine but none have looked at adverse outcomes in large numbers. STUDY DESIGN An observational study of all patients prescribed thyroid hormone replacement in Tayside Scotland (population 400 000) from 1997 to 2014. PATIENTS A study group of patients having ever used liothyronine (n = 400) was compared to those who had only used l-thyroxine (n = 33 955). All patients were followed up until end-point, death or leaving Tayside. MEASUREMENTS Mortality rates and admissions with cardiovascular disease, atrial fibrillation, fractures, breast cancer and mental diseases were compared. Incident use of bisphosphonates, statins, antidepressants and antipsychotics was compared. RESULTS Compared to patients only taking l-thyroxine, those using liothyronine had no increased risk of cardiovascular disease [hazard ratio (HR) 1·04; 95% CI 0·70-1·54], atrial fibrillation (HR 0·91: 0·47-1·75), or fractures (HR 0·79: 0·49-1·27) after adjusting for age. There was no difference in the number of prescriptions for bisphosphonates or statins. There was an increased risk of new prescriptions for antipsychotic medication (HR 2·26: 1·64-3·11 P < 0·0001) which was proportional to the number of liothyronine prescriptions. There was a non-significant trend towards an increase in breast cancer and new use of antidepressant medications. During follow-up, median TSH was higher for patients on l-thyroxine alone (2·08 vs 1·07 mU/L; P < 0·001). CONCLUSION For patients taking long-term liothyronine we did not identify any additional risk of atrial fibrillation, cardiovascular disease or fractures. There was an increased incident use of antipsychotic medication during follow-up.
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Affiliation(s)
- Graham P Leese
- Department of Endocrinology and Diabetes, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Enrique Soto-Pedre
- Division of Cardiovascular & Diabetes Medicine, School Of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Louise A Donnelly
- Division of Cardiovascular & Diabetes Medicine, School Of Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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Thyroid hormones and their membrane receptors as therapeutic targets for T cell lymphomas. Pharmacol Res 2016; 109:55-63. [PMID: 26855318 DOI: 10.1016/j.phrs.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/25/2016] [Accepted: 02/01/2016] [Indexed: 12/29/2022]
Abstract
Thyroid hormones (THs) are important regulators of metabolism, differentiation and cell proliferation. They can modify the physiology of human and murine T cell lymphomas (TCL). These effects involve genomic mechanisms, mediated by specific nuclear receptors (TR), as well as nongenomic mechanisms, that lead to the activation of different signaling pathways through the activation of a membrane receptor, the integrin αvβ3. Therefore, THs are able to induce the survival and growth of TCL. Specifically, the signaling induced by THs through the integrin αvβ3 activates proliferative and angiogenic programs, mediated by the regulation of the vascular endothelial growth factor (VEGF). The genomic or pharmacologic inhibition of integrin αvβ3 reduces the production of VEGF and induces cell death both in vitro and in xenograft models of human TCL. Here we review the mechanisms involved in the modulation of the physiology of TCL induced by THs, the analysis of the interaction between genomic and nongenomic actions of THs and their contribution to T cell lymphomagenesis. These actions of THs suggest a novel mechanism for the endocrine modulation of the physiopathology of TCL and they provide a potential molecular target for its treatment.
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Wang Z, Wang Y, Lv F, Liu X, Jia C, Chen X, Han T. An Effective Method for Monitoring Three Iodothyronines in Meat Tissue and Eggs by Liquid Chromatography–Tandem Mass Spectrometry. FOOD ANAL METHOD 2015. [DOI: 10.1007/s12161-015-0091-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Thyroid hormone receptor α in breast cancer: prognostic and therapeutic implications. Breast Cancer Res Treat 2014; 149:293-301. [PMID: 25542270 DOI: 10.1007/s10549-014-3235-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/05/2014] [Indexed: 10/24/2022]
Abstract
We determined the expression of two transcriptional variants of thyroid hormone receptor alpha (THRα1 and THRα2) in samples from a cohort of breast cancer patients and correlated expression levels with survival. 130 women who were diagnosed with invasive breast carcinoma between 2007 and 2008 were included. Representative sections of their tumours were analyzed in triplicate on a tissue microarray for expression of THRα1 and THRα2 by immunohistochemistry. The prognostic significance of THRα1 and THRα2 expression was assessed using Kaplan-Meier survival analyses, adjusted for known prognostic factors. Seventy-four percent of tumours had high expression of THRα1 (Allred score ≥6) and 40 % had high expression of THRα2. Expression of THRα2 correlated positively with ER expression (p < 0.001) and with PR expression (p < 0.001), but negatively with HER2 expression (p = 0.018). Patients with low THRα2 expression had inferior 5-year overall survival (75.3 %) compared to those with high expression (91.7 %; p = 0.06). In a multivariate model, high THRα2 expression was a significant and independent prognosticator of improved overall survival (HR = 0.84; 95 % CI 0.71-0.98). Many breast tumours express THRα2 at high levels and these patients experience improved survival. Thyroid hormone signalling may be important in a proportion of breast cancers and THRα2 expression may be a regulator of signalling in this pathway.
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