Vitamin D3 levels and insulin resistance in papillary thyroid cancer patients

Calcitriol suppresses gastric cancer progression and cisplatin resistance by inhibiting glycolysis and M2 macrophage polarization through inhibition of mTOR activation

The tumor microenvironment (TME) plays a critical role in tumor progression, with macrophages and tumor cells interacting within the TME, influencing cancer development. Despite the known anticancer properties of calcitriol, its role in the TME remains uncertain. This study aimed to explore the effects of calcitriol on macrophages and cancer cells in the TME and its impact on gastric cancer cell proliferation and cisplatin resistance. In vitro TME models were established using conditioned medium from gastric cancer cells (CCM) and macrophages (MCM) treated with or without calcitriol. The results revealed that calcitriol treatment suppressed the expression of glycolysis-related genes and proteins (GLUT1, HKII, LDHA) in MCM-induced gastric cancer cells, leading to increased cancer cell apoptosis and reduced viability, along with decreased Cyclin D1 gene expression. Moreover, calcitriol treatment inhibited mTOR activation in MCM-induced gastric cancer cells. Additionally, calcitriol hindered CCM-induced M2 macrophage polarization by reducing CD206 expression and increasing TNFα gene expression in THP1-derived macrophages, attenuating cisplatin resistance. These findings suggest that calcitriol may impede gastric cancer progression by targeting glycolysis and M2 macrophage polarization through the regulation of mTOR activation in the TME.

The relationship of pre-operative vitamin D and TSH levels with papillary thyroid cancer

OBJECTIVE

Our goal in this study is to analyze the correlation between papillary thyroid cancer (PTC) with elevated thyroid-stimulating hormone (TSH) levels and deficiency of vitamin D.

METHODS

Patients who underwent thyroidectomy, also with available vitamin D test results preoperatively, were included in the study. The patients were separated into two different categories as having papillary thyroid carcinoma (Group 1), benign diseases (Group 2). According to the TSH (mUI/mL) level and vitamin D values, patients were categorized into four quarters.

RESULTS

Preoperatively, TSH level (mean±SDmUI/mL) was higher in Group 1 (2.04±1.55) compared to Group 2 (1.82±1.94) significantly (p=0.029). Preoperatively, vitamin D levels (mean±SD) were higher in Group 1 (15.88±10.88) than in Group 2 (12.94±10.26) significantly (p=0.011). There was no significant difference between Group 1 and Group 2 according to the vitamin D deficiency (65.5%, 72.8%; respectively (p=0.472)). When categorized with reference to pre-operative vitamin D levels, the proportion of patients in Group 2 and Category 1 was higher significantly (p=0.031).

CONCLUSION

Although the pre-operative TSH level was significantly higher in papillary thyroid carcinoma than benign thyroid diseases, the categorical distributions of the patients according to the TSH value were similar and the TSH values overlapped. Pre-operative mean vitamin D levels were similar in both PTC and benign thyroid disease groups so PTC was not associated with vitamin D deficiency.

Association Between Papillary Thyroid Carcinoma and Vertebral Fracture

Suppression of TSH levels associated with levothyroxine treatment is a known risk factor for fracture. However, it is unclear whether patients with papillary thyroid carcinoma (PTC) have a higher risk of vertebral fracture (VF) before TSH suppression. The aim of the study was to examine whether the risk of VF is higher in PTC than in healthy subjects. A hospital-based, matched case-control study was conducted comparing PTC and healthy individuals. We enrolled 43 postoperative patients with PTC scheduled for radioiodine therapy and 43 age- and sex-matched healthy controls. Serum and urinary biological parameters, bone mineral density (BMD), and presence of VFs were evaluated in both groups. We compared these indices using χ2 and Mann-Whitney U-test and analyzed the association between PTC and VF by logistic regression analysis. The PTC group had higher BMI, HbA1c and phosphorus, and lower intact PTH than the control group. Lumbar and femoral neck BMD did not differ between the two groups. Prevalence of VFs was significantly higher in the PTC group (44.1%) than in the control group (16.3%). Multivariate logistic regression analyses adjusted for age, sex, and BMI identified PTC as being associated with the presence of VFs (odds ratio, 5.63; 95% confidence interval: 1.82 to 17.5). This relationship remained significant after additional adjustment for HbA1c and BMD. There is an association between PTC and a risk of VF independent of sex, BMI, glucose metabolism, and BMD, suggesting the importance of fracture risk assessment before TSH suppression.

Vitamin D Status in Patients before Thyroidectomy

Thyroid neoplasms (tumors) are the most common pathology of the endocrine system that requires surgery, and in most cases changes are benign. The surgical treatment of thyroid neoplasms consists in total, subtotal, or one lobe excision. Our study aimed to assess the concentration of vitamin D and its metabolites in patients before thyroidectomy. The study included 167 patients with thyroid pathology. Before the thyroidectomy procedure calcidiol (25-OHD), calcitriol (1,25-(OH)₂D), and vitamin D binding protein (VDBP), as well as basic biochemical parameters, were measured using an enzyme-linked immunosorbent assay kit. Data analysis showed that the cohort of patients has a significant 25-OHD deficiency and proper concentration of 1,25-(OH)₂D. Before the surgery, more than 80% of patients have extreme vitamin D deficiency (<10 ng/mL), and only 4% of the study group has proper 25-OHD concentration. Patients undergoing thyroidectomy are exposed to many complications, including calcium reduction. Our research has shown that patients prior to surgery have a marked vitamin D deficiency, an indicator that may affect their subsequent convalescence and prognosis. The results suggest that determination of vitamin D levels prior to thyroidectomy may be useful for potential consideration of supplementation when vitamin D deficiency is marked and needs to be incorporated into the good clinical management of these patients.

Blood Profiles in the Prediction of Radioiodine Refractory Papillary Thyroid Cancer: A Case-Control Study

Purpose

Although most patients with papillary thyroid cancer can be cured by surgery and I-131 ablation, a small proportion will progress to radioactive iodine refractory (RAIR) thyroid cancer. The prediction of RAIR in its early stages can improve patient prognosis. The aim of this article is to evaluate the blood biomarkers in patients with RAIR and to establish a prediction model.

Patients and Methods

Data collected from patients with thyroid cancer that were enrolled from Jan. 2017 to Dec. 2021 were screened. RAIR was defined based on the criteria in the 2015 American Thyroid Association guidelines. The blood biomarkers from the study participants at three admissions timepoints (surgery and first and secondary I-131 ablations) were compared using both parametric and nonparametric tests to identify predictive factors for RAIR. Binary logistic regression analysis was used to construct a prediction model using parameters associated with surgical procedure decision. The model was then assessed with receiver operating characteristic curves.

Results

Thirty-six patients were included in the data analysis. Sixteen blood variables, including the low density lipoprotein-cholesterol-total cholesterol ratio, neutrophils, thyroglobulins, thyroglobulin antibody, thyroid peroxidase antibody, anion gap, etc., were revealed to be predictors for RAIR. The prediction model, which incorporated two parameters, reached an area under the curve of 0.861 (p<0.001).

Conclusion

Conventional blood biomarkers can be used in the prediction of early-stage RAIR. In addition, a prediction model incorporating multiple biomarkers can improve the predictive accuracy.

The effect of serum 25-hydroxy vitamin D levels on malignancy in exophytic thyroid nodules

Aim: The increase in the incidence of thyroid cancer brings about research of new risk factors. In this study, we aimed to investigate the effect of vitamin D status on malignancy in exophytic nodules. Material and Method: Two hundred and sixteen patients with exophytic thyroid nodules were included in the study. All patients’ thyroid nodule ultrasonographic features, fine needle aspiration biopsy cytology results, rate of surgery and surgery histopathological results were recorded. Vitamin D levels were analyzed and patients were divided into two groups as vitamin D sufficient groups (vitamin D≥20 ng/ml) and vitamin D deficient group (vitamin D&lt;20 ng/ml). Results: Malignancy rate was significantly higher in the vitamin D deficient group (%19 vs %8.7; p=0.03). There were no significant difference between two groups in terms of demographic characteristics and ultrasonographic features including diameter, hypoechoic nature, having irregular border and microcalcifications. Conclusion: In exophytic nodules, vitamin D deficiency increases malignancy risk. Determining vitamin D levels may be useful in patients with exophytic nodules.

Hypertension Was Associated with Higher Tumor Stages in Papillary Thyroid Cancer: A Large Sample Single-Center Study

Background: Hypertension (HTN) is known to increase the risk of thyroid cancer. However, few studies have explored the association between HTN and the prognostic factors of papillary thyroid cancer (PTC). Methods: We retrospectively evaluated 2838 PTC patients treated with surgery at our center between January 2017 and September 2020. The association between both HTN and antihypertensive drug use and the clinicopathological features of the PTC patients was analyzed. The odds ratios (ORs) were estimated using both univariate and multivariate logistic regression models, which were adjusted for the patients' age, sex, and thyroid-stimulating hormone level. Results: A total of 2838 patients were enrolled in this study, including 409 patients with HTN. In the multivariate analysis, HTN was associated with larger tumor size [OR = 1.51, 95% confidence interval (CI): 1.10-2.07], lymph node metastasis (OR = 1.43, 95% CI: 1.02-1.99), and higher tumor stages (OR = 1.79, 95% CI: 1.12-2.86). There was no statistical difference between females >40 years of age and any pathological features, while a positive association was observed between older males and larger tumors (OR = 1.87, 95% CI: 1.01-3.45), and lymph node metastasis (OR = 2.01, 95% CI: 1.08-3.73). No statistical difference was found in the effects of taking alone calcium channel blockers, angiotensin-converting enzyme inhibitors/angiotensin II-receptor blockers, and their combination on the pathological features of PTC. Conclusion: PTC patients with HTN, particularly males of age >40, tend to have invasive features. Common antihypertension therapy appears to exert no effect on the pathological characteristics of these patients.

Role of Dietary and Environmental Factors on Thyroid Cancer in Romania: A Brief Review

Thyroid cancer is the most common endocrine tumor, accounting for about 1% of all human malignancies. There are environmental factors that can potentiate the onset of thyroid cancer, in particular pollutants, lifestyle or radiation exposure. Another major cause responsible for the appearance of thyroid cancer is the habitat in endemic areas where there is a deficit of iodine in the soil, drinking water and food. We operated using the PubMed database in order to find the articles of interest. After a wary review of the literature, we designated the relevant articles necessary for our study including various factors such as alimentation, effects of the Chernobyl fallout radiation and the iodine and vitamin D deficiency in Romania. The aim of this article is to make a correlation between the different environmental and dietary factors in Romania, and the increased incidence of thyroid cancer.

Relationship between insulin resistance and thyroid cancer in Chinese euthyroid subjects without conditions affecting insulin resistance

BACKGROUNDS

In recent years, many studies have shown that insulin resistance is related to the occurrence of thyroid cancer, but there are few reports on whether the two are related under the premise that thyroid function is normal and the metabolic components related to insulin resistance are excluded. This study aims to analyze the insulin resistance of patients with differentiated thyroid cancer after excluding the population with abnormal metabolic components, and to study the risk factors of thyroid cancer in this population.

METHODS

61 subjects diagnosed with differentiated thyroid carcinoma (DTC) formed the DTC group and 262 subjects with benign nodules formed the control group. Body mass index (BMI, kg/m2), waist circumference (WC), lipid profiles, and free T3 (FT3), free T4 (FT4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), thyroid globulin antibody (TGAb), alanine transaminase (ALT), aspartate aminotransferase (AST), fasting plasma glucose (FPG), fasting serum insulin and homeostatic model assessment of insulin resistance (HOMA-IR) levels were measured.

RESULTS

Mean subjects age (P = 0.021), BMI (P = 0.049), WC (P = 0.01), serum insulin concentration (P = 0.006), and HOMA-IR level (P = 0.005) were significantly greater in the DTC group than in the control group. Multivariate binary logistic regression analysis identified advanced age (OR = 1.027 [1.003-1.051], P = 0.029) and an increased HOMA-IR level (OR = 1.572 [1.277-1.935], P < 0.001) as significant risk factors for thyroid cancer.

CONCLUSIONS

IR may increase the risk of thyroid cancer development even in the absence of conditions affecting insulin resistance.

Relationship Between Vitamin D and Thyroid: An Enigma

Hypothyroidism is a frequently encountered endocrine disorder in clinical practice. Besides its traditional role in bone health, vitamin D has been shown to have favorable effects in a variety of different systems due to its pleiotropic qualities and ubiquitous receptor expression. Over the years, researchers have been fascinated by the intricate molecular interplay between vitamin D and thyroid. In this regard, attempts have emerged to demonstrate the role of vitamin D in thyroid disorders. This article has reviewed the existing literature on the role of vitamin D in hypothyroidism. We explored studies discussing the physiological interactions between vitamin D and thyroid, as well as the clinical consequences, supplemental and prognostic relevancy of vitamin D in auto-immune thyroid disease (AITD) and hypothyroidism.

Abnormal Glucose Metabolism Parameters and the Aggressiveness of Differentiated Thyroid Carcinoma: A Hospital-Based Cross-Section Study in China

PURPOSE

The correlation of abnormal glucose metabolism and thyroid carcinoma, especially the aggressiveness of thyroid cancer, still remains controversial. We conducted this study to investigate the relationship between abnormal glucose metabolism parameters and differentiated thyroid carcinoma (DTC) in the Chinese population.

MATERIALS AND METHODS

The study was designed as a hospital-based case-control study and was approved by the Ethics Committee of our hospital and registered in the Clinical Trial Protocol Registration and Results System (Registration code: NCT03006289). From January 1, 2018 to June 30, 2021, a total of 377 DTC patients were enrolled in the study. Demographic and general characteristics, details of thyroid surgery and histopathological results, hematological test indicators were collected. Glucose metabolism parameters were calculated. Variables were analyzed by t-test, ANOVA, chi-squared analysis and Fisher's exact test. Pearson bi-variate correlation and Spearman's correlation analysis were used for bi-variate analysis.

RESULTS

More than 40% of patients with DTC were multifocality, more than half were extra-glandular invasion, and nearly 85% complied by lymph node metastasis. The prevalence of diabetes mellitus (DM) was about 10.08% in DTC patients. It was found that the proportion of postprandial 2 h blood glucose ≥11.1mmol/L and HbA1c ≥6.5% was significantly higher than the known proportion of DM (17.8%, 16.7% vs. 10.08%). Additionally, 87.3% of the DTC patients in this study had varying degrees of insulin resistance. Further analysis found that higher T staging was associated with higher levels of area under curve of C-peptide (P = 0.029), insulin sensitivity index (P = 0.012) and C-peptide sensitivity index (P = 0.016). A delayed peak of insulin secretion was found to be positive related with capsule invasion (r = 0.206, P = 0.004). In patients without a DM history, homeostasis model assessment of insulin resistance (P = 0.017), insulin sensitivity index (P = 0.019) and C-peptide sensitivity index (P = 0.020) were statistic associated with T staging. Also, the glucose metabolism parameter at 3-hour after a meal was related to a larger number of metastatic lymph nodes.

CONCLUSION

Abnormal glucose metabolism, namely, DM, hyperinsulinemia and insulin resistance, were significantly associated with the carcinogensis and aggressiveness of DTC.

High prevalence of thyroid carcinoma in patients with insulin resistance: a meta-analysis of case-control studies

The association between insulin resistance and thyroid carcinoma is controversial. We conducted this meta-analysis of association between insulin resistance and thyroid carcinoma. There were 14 studies included in this meta-analysis. Random-effect model was used to merge the weighted mean difference value of fasting serum insulin level and the pooled effect shows that the level of fasting serum insulin is higher in patients with thyroid carcinoma than those of controls (1.88, 95% CI 0.87 to 2.90, P=0.0003). Random-effect model was used to estimate the pooled weighted mean difference and it shows that thyroid carcinoma patients have a higher level of homeostasis model assessment of insulin resistance (HOMA-IR) than patients without thyroid carcinoma (0.54, 95% CI 0.29 to 0.78, P<0.0001). Fixed-effect model with the odds ratio of insulin resistance shows that insulin resistance could increase the risk of thyroid carcinoma 216% compared with participants without insulin resistance (3.16, 95% CI 2.09 to 4.77, P<0.0001). In conclusion, insulin resistance might be a risk factor for thyroid carcinoma.

The Role of Vitamin D as a Prognostic Marker in Papillary Thyroid Cancer

Simple Summary

Thyroid cancer is the most common endocrine malignancy in the United States and papillary thyroid cancer is by far the most common subtype. Vitamin D has been postulated as a key modulator in several cancer-related pathways, although its contributions to thyroid cancer remain controversial. In this paper, we review the metabolic pathways of vitamin D and explore potential links to cancer-related mechanisms. In addition, we also explore the medical literature related to vitamin D as a prognostic marker for staging in papillary thyroid cancer.

Abstract

The role of vitamin D in modulating several cancer-related pathways has received an increasing amount of attention in the past several years. Previous literature has found an abundance of evidence of vitamin D exerting an anti-proliferative, anti-inflammatory, and pro-differentiation effect in various types of cancers including breast, colon, prostate, and pancreatic cancer. Although the link between vitamin D and thyroid cancer remains controversial, both biochemical evidence and clinical studies have attempted to establish a link between papillary thyroid carcinoma (PTC) and vitamin D status. Furthermore, the use of vitamin D as a prognostic marker has received increased attention, both in regards to clinical outcomes and cancer staging. In this review, we briefly discuss the metabolism and proposed mechanism of action of vitamin D in the context of PTC, and explore links between modulators in the vitamin D pathway and progression of PTC. We provide evidence from both clinical studies as well as molecular studies of metabolic targets, including vitamin D receptor and activating enzymes exerting an effect on PTC tissue, which indicate that vitamin D may play a significant prognostic role in PTC.

The Role of Vitamin D, Platelet-Derived Growth Factor and Insulin-Like Growth Factor 1 in the Progression of Thyroid Diseases

Background:

Thyroid cancer (TC) is a common malignant tumor, however the role of total vitamin D: 25(OH)D, Platelet Derived Growth Factor (PDGF) and Insulin Like Growth Factor 1 (IGF-1) in the development of TC is still unclear.

Aim:

To assess the roles of 25(OH)D, PDGF and IGF-1 in the progression of thyroid diseases. METHODS: The serum levels of 25(OH)D, PDGF and IGF-1 were assessed in 70 patients with papillary thyroid cancer (PTC), 60 patients with benign thyroid nodules (BN) compared to 60 normal controls (NC) using ELISA technique.

Results:

There was a significant decrease in the serum level of 25(OH)D in TC patients compared to NC (P<0.001) and BN patients (P=0.006). There was a significant increase in the serum levels of PDGF and IGF-1 in TC patients (P<0.001), and BN patients (P<0.001) compared to NC, while there were no significant differences between TC and BN (P=0.087, and 0.258; respectively). PDGF correlated significantly with IGF-1 (r=0.412, P<0.001), TSH (r=0.146, P=0.045), and inversely correlated with 25(OH)D (r= -0.156, P=0.013) and FT4 (r=-0.178, P=0.014). There was a significant inverse correlation between the serum levels of IGF-1 and FT4 (r=-0.172, P=0.017). Sensitivity and specificity for assessment of TC patients were (65.7% and 58.3%, P= 0.001) for 25(OH)D, (65.7% and 58.3%, P=0.021) for IGF-1, and (68.6% and 61.7%, P=0.006) for PDGF. Multivariate analysis demonstrated that serum 25(OH)D (OR=0.578, 95%CI= 0.426-0.783), IGF-1 (OR=1.019, 95%CI= 1.010-1.029) and PDGF (OR=1.007, 95%CI= 1.004-1.009) were considered independent risk factors for thyroid cancer (P<0.001, for all).

Conclusion:

25(OH) D, IGF-1 and PDGF are significantly different in TC and BN cases compared to control. They have an important role in the progression of TC. However, these data should be validated on a larger sample size.

Medullary thyroid cancer is associated with high serum vitamin D level and polymorphism of vitamin D receptors

Background

Thyroid cancer is the most common endocrine malignancy. Studies have observed an anti-cancer effect for vitamin D and found that polymorphisms of vitamin D receptors can influence the prevalence of various cancers. The present study investigated the serum level of vitamin D and FokI, BsmI and Tru9I polymorphisms of vitamin D receptors.

Methods

Forty patients with medullary thyroid cancer and 40 healthy controls were investigated. The genomic DNA of the subjects was extracted using saturated salt/proteinase K and investigated by PCR sequencing. Serum levels of vitamin D were evaluated by ELISA. The results were analyzed in SPSS and GraphPad Prism 5 software.

Results

The genotypic and allelic frequencies of FokI and BsmI polymorphisms showed no significant differences between test and control groups. For Tru9I polymorphism, Tt genotype and t allelic frequency in the test group were significantly different from those of the control group. Also, we found Tt genotype and t allelic frequency to be significantly associated with medullary thyroid cancer (MTC) type and the agressiveness of the disease. The average serum vitamin D level was 23.32 ng/mL and 18.95 ng/mL for patients and controls, respectively, and the difference between the two groups was statistically significant. Moreover, we found high serum vitamin D level to be associated with t allelic frequency.

Conclusions

Unexpectedly, the mean serum vitamin D level of the test group was significantly higher than that of the control group. Tru9I polymorphism was found to be significantly correlated with the prevalence of medullary thyroid carcinoma.

Immunomodulatory Effects of Vitamin D in Thyroid Diseases

Vitamin D is a secosteroid with a pleiotropic role in multiple physiological processes. Besides the well-known activity on bone homeostasis, recent studies suggested a peculiar role of vitamin D in different non-skeletal pathways, including a key role in the modulation of immune responses. Recent evidences demonstrated that vitamin D acts on innate and adaptative immunity and seems to exert an immunomodulating action on autoimmune diseases and cancers. Several studies demonstrated a relationship between vitamin D deficiency, autoimmune thyroid disorders, and thyroid cancer. This review aims to summarize the evidences on the immunomodulatory effect of vitamin D on thyroid diseases.

Papillary thyroid carcinoma is a risk factor for severe osteoporosis

INTRODUCTION

Thyroid-stimulating hormone (TSH)-suppressive therapy is recommended after surgical treatment in high-risk papillary thyroid carcinoma (PTC) patients. TSH-suppressive therapy is a known risk factor for osteoporosis and fractures. However, whether patients with PTC themselves are at a higher risk of osteoporosis than healthy individuals remains unclear. This study aimed to clarify whether PTC is a risk factor for osteoporosis.

MATERIALS AND METHODS

Serum and urinary biochemical parameters, bone mineral density (BMD), and presence of vertebral fractures (VFs) and non-VFs were evaluated in 35 PTC patients and 35 age- and sex-matched healthy individuals. We compared the parameters between PTC and control subjects and performed multiple logistic regression analyses after adjustments for variables.

RESULTS

Patients with PTC had higher body mass index (BMI) and hemoglobin (Hb)A1c, as well as lower eGFR and intact PTH than controls (p < 0.05, each). There were no significant differences in the prevalence of osteoporosis and VFs and non-VFs between patients with PTC and controls. However, the prevalence of severe osteoporosis diagnosed according to WHO criteria was significantly higher in PTC subjects (34.3%) than in controls (11.4%, p < 0.05). Multivariate logistic regression analyses adjusted for age, BMI, eGFR and HbA1c identified PTC as being associated with the presence of severe osteoporosis (odds ratio, 4.20; 95% confidence interval, 1.05-16.8; p < 0.05).

CONCLUSIONS

We identified PTC as a risk factor for severe osteoporosis, independent of BMI, renal function and glucose profile.

Nutritional status and follicular-derived thyroid cancer: An update

The incidence of differentiated thyroid cancer has been increasing in the last decades all over the world. Such a steady growth cannot be entirely attributable to more intensive thyroid nodule screening and more sensitive diagnostic procedures. Several environmental factors have changed with sufficient rapidity in the same time frame and may represent credible candidates for this increase. They include modified iodine intake, lifestyle-associated risk factors, exposure to various toxic compounds, pollutants and xenobiotics, nutritional deficiencies, eating habits and comorbidities. Foremost, nutritional patterns have gained high interest as possible promoters and modifiable risk factors for thyroid cancer in recent years. The aim of this narrative review is to focus on the relationship between thyroid cancer and nutritional factors, dietary habits and obesity. Low iodine intake has been associated to increased risk of thyroid cancer, favoring the development of more aggressive histotypes. Moreover, correction of iodine deficiency can shift thyroid cancer subtypes toward less aggressive forms, without affecting the overall risk for cancer. Actually, evidence regarding the association between selenium and vitamin D deficiency and thyroid cancer is very limited, despite their well-known anti-cancer potentials, and the clinical usefulness of their supplementation is still uncertain in this setting. Albeit the relationship between single foods and thyroid cancer is difficult to examine, fish and iodine-rich foods, vegetables, and fruits might exert protective effects on thyroid cancer risk. Conversely, no clear association has been found for other foods to date. Lastly, a clear association between obesity and the risk of thyroid cancer, with more aggressive behavior, seems to emerge from most studies, likely involving variations in thyroid function and chronic inflammation mediated by cytokines, insulin, leptin and adiponectins. Although no definite association between dietary factors and thyroid cancer has been firmly established so far, some nutritional patterns, together with excessive weight, seem to play a relevant role in thyroid cancer carcinogenesis as well as in its severity and aggressiveness. These effects may play an additive role to the well-established one exerted by environmental carcinogens, such as pollutants and radiation exposure.

Vitamin D, Thyroid Autoimmunity and Cancer: An Interplay of Different Factors

BACKGROUND AND AIMS

In spite of large volume of data linking Vitamin D with cardiovascular morbidity, autoimmunity, cancer, and virtually every organ system, Vitamin D and thyroid is a lesser-known aspect of Vitamin D in clinical practice. This article intends to highlight the current literature on the impact of Vitamin D status and supplementation on thyroid autoimmunity and cancer.

METHODS

References for this review were identified through searches of PubMed for articles published to from 1950 to August 2019 using the terms "thyroid" [MeSH Terms] AND "Vitamin D" [MeSH Terms] OR "thyroid" [All Fields] AND "Vitamin D" [All Fields].

RESULTS

Significant inverse correlation was documented between anti-thyroid peroxidase antibody (TPOAb) and serum 25-hydroxy-Vitamin D (25OHD). TPOAb positivity is more prevalent in Vitamin D deficient individuals. A large volume of medical literature is available from observational studies linking Vitamin D with thyroid autoimmunity. Data from interventional studies documenting beneficial effects of Vitamin D on thyroid autoimmunity is also available, but lesser than that from observational studies. Short-term high dose oral Vitamin D supplementation reduces TPOAb titers. Certain Vitamin D receptor (VDR) gene polymorphism have been linked to increased occurrence of autoimmune thyroid disorders (AITD). Vitamin D deficiency, decreased circulating calcitriol has been linked to increased thyroid cancer. Certain VDR gene polymorphisms have been linked with increased as well as decreased occurrence of thyroid cancer. Data is scant on use of Vitamin D and its analogues for treating thyroid cancer.

CONCLUSION

In spite of large volume of medical literature from observational studies linking Vitamin D with thyroid autoimmunity and cancer, meaningful concrete clinical data on impact of Vitamin D supplementation on hard clinical end points in these disorders is lacking, and should be the primary area of research in the next decade.

Hyperinsulinemia and thyroid peroxidase antibody in Chinese patients with papillary thyroid cancer

This study aimed to investigate if hyperinsulinemia and/or insulin resistance was correlated with the occurrence of papillary thyroid cancer (PTC) in a group of Chinese patients. 258 inpatients were included in the study. According to the postoperative pathology results, all subjects were divided into PTC (n = 153) and control groups (with benign thyroid nodules, n = 105). Body mass index (BMI), fasting glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), thyroid-stimulating hormone (TSH), FT4, FT3, thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb), serum uric acid (UA), and lipid levels. Fasting insulin levels, HOMA-IR values, TPOAb levels, serum TSH levels, and serum uric acid levels in the PTC group were higher than those in the control group (p < 0.05). However, no significant differences in age, gender, BMI, history of hypertension, and the levels of fasting plasma glucose, FT3, FT4, TGAb, total cholesterol, triglyceride, low-density lipoprotein, and high-density lipoprotein were observed between the two groups (p > 0.05). After the multiple logistic regression analysis, the occurrence of PTC was positively associated with fasting insulin (odds ratio [OR] = 1.048, 95% confidence interval [CI]: 1.003-1.096, p = 0.037) and TPOAb levels (OR = 1.001, 95% CI: 1.000-1.002, p = 0.032). Moreover, TPOAb level was positively correlated with vague margin (r = 0.126, p = 0.045) and negatively correlated with homogeneous echo (r = -0.179, p = 0.004). However, fasting insulin levels were not correlated with pathological characteristics of PTC. Hyperinsulinemia and higher TPOAb levels might be the risk factors of PTC, but not disease severity in Chinese patients.

VDR gene FokI polymorphism as a poor prognostic factor for papillary thyroid cancer

This is the first study to investigate the effect of vitamin D receptor ( VDR) gene single-nucleotide polymorphisms on the clinicopathologic features of papillary thyroid cancer in Turkey. A total of 165 patients with papillary thyroid cancer and 172 controls were included in this case-control study. VDR gene single-nucleotide polymorphisms FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) were evaluated using reverse-transcription polymerase chain reaction. VDR gene polymorphisms BsmI, ApaI, and TaqI did not differ between the papillary thyroid cancer group and control group (p > 0.05, each). BsmI, ApaI, and TaqI were not associated with papillary thyroid cancer risk. The VDR gene FokI CT/TT genotype was associated with an increased papillary thyroid cancer risk (CT vs CC: odds ratio = 1.71, 95% confidence interval = 1.15-2.76, p = 0.028; TT vs CC: odds ratio = 2.44, 95% confidence interval = 1.29-4.62, p = 0.005; CT/TT vs CC: odds ratio = 1.88, 95% confidence interval = 1.20-2.96, p = 0.006; CT/CC vs TT: odds ratio = 1.80, 95% confidence interval = 1.05-3.20, p = 0.041). VDR gene polymorphisms were not in linkage disequilibrium. The FokI TT genotype was associated with having T3 and T4, stage III/IV, extra-thyroidal invasion. The FokI CT/TT or TT genotype was associated with developing N1 status, multifocality, tumor size ≥10 mm, and treatment with radioiodine therapy. Persistence/recurrence did not differ between the FokI genotypes. Carriers of the FokI T allele were at an increased risk of more advanced tumor-node-metastasis stage, greater tumor size, multifocality, and extra-thyroidal invasion of papillary thyroid cancer compared with the CC genotype. VDR gene FokI T allele and TT genotype correlated with aggressiveness of papillary thyroid cancer; thus, FokI could be useful as a poor prognostic factor to assess the high risk of papillary thyroid cancer.

Association between vitamin D deficiency and risk of thyroid cancer: a case-control study and a meta-analysis

PURPOSE

Although vitamin D is reportedly associated with various cancers, the association between vitamin D and thyroid cancer is indefinite. We aimed to investigate whether this association applies to thyroid cancer (TC).

METHODS

A total of 276 Chinese Han people were recruited in a current matched case-control study. Multivariable conditional logistic regression was computed to estimate the association between plasma 25(OH)D and papillary thyroid cancer (PTC). In addition, we searched relevant studies in PubMed and Web of Science databases before December 2017 to conduct a meta-analysis.

RESULTS

In our case-control study, plasma 25(OH)D concentration was inversely associated with PTC risk (highest tertile vs lowest tertile: adjusted OR = 0.25; 95% CI 0.10, 0.61; P_trend = 0.003). This association was independent of body mass index and physical activity (all adjusted P_interaction > 0.05). A total of 11 studies were included in the meta-analysis, among which ten studies have been published and one was our case-control study. Compared with 25(OH)D non-deficient group, the pooled OR of TC was 1.42 (95% CI 1.17, 1.73) in the deficient group. Similarly, blood 25(OH)D levels in patients with TC were tend to be lower than those in the controls (SMD = - 0.20, 95% CI - 0.36, - 0.03).

CONCLUSIONS

A high level of circulating 25(OH)D was associated with a decreased TC risk. This association has important significance in public health and should, therefore, be further studied.

The association between thyroid cancer and insulin resistance, metabolic syndrome and its components: A systematic review and meta-analysis

BACKGROUND

Thyroid cancer is rapidly increasing in incidence worldwide in the past several decades, same as the incidence of metabolic syndrome. We performed a system review and meta-analysis of the association between metabolic syndrome, its components and insulin resistance and thyroid cancer incidence.

METHODS

We searched several computer-assisted databases PUBMED, EMBASE and ISI Web of Science to identify studies published before 31st January 2018. Every study must report either risk estimates of thyroid cancer incidence with 95% confidence interval (CI) or related data can speculate. Two investigators independently identified eligible studies and extracted data. Evaluating the summaries of relative risk estimates use both fixed and random effects methods.

RESULTS

We found 42 articles met the inclusion criteria of this review. There is an increased risk for thyroid cancer for patients with insulin resistance (relative risk [RR] = 1.59, 95%confidence interval [CI] = 1.12-2.27, P = 0.01), dysglycemia (RR = 1.40, 95%CI = 1.15-1.70,P < 0.001), high BMI (RR = 1.35,95%CI = 1.23-1.48,P < 0.001) and hypertension(RR = 1.34,95%CI = 1.22-1.47, p < 0.001). However, patients with dyslipidemia, both total cholesterol (RR = 1.09, 95%CI = 0.98-1.21, P = 0.13) and triglyceride (RR = 1.01, 95%CI = 0.91-1.12, P = 0.82) was not associated with thyroid cancer.

CONCLUSIONS

Our meta-analysis showed Insulin Resistance, dysglycemia, high BMI and hypertension significantly increased the thyroid cancer risk. These results may help identify people with high risk of thyroid cancer and change to healthy life style.

Vitamin D deficiency as a risk factor for thyroid cancer: A meta-analysis of case-control studies

OBJECTIVE

The association between vitamin D deficiency and thyroid cancer is controversial. Some studies have demonstrated that higher serum vitamin D levels might protect against thyroid cancer, whereas others have not, or have even indicated the opposite to be the case. The aim of this meta-analysis was to investigate the association between vitamin D deficicency and thyroid cancer and propose that vitamin D deficiency is a risk factor for thyroid cancer.

METHODS

This was a meta-analysis of 14 articles of the association between vitamin D deficiency and thyroid cancer. Databases including PubMed, Cochrane library, Sinomed, CNKI, Wanfang, and clinical trial register centers, were searched for case-control studies of vitamin D in thyroid cancer.

RESULTS

Fourteen studies were included in this meta-analysis. A fixed-effect model was used to merge the standardized mean difference value of serum 25-hydroxyvitamin D levels. The pooled effect showed that the levels of serum 25-hydroxyvitamin D were lower in patients with thyroid cancer preoperatively than in the controls (-0.22; 95% confidence interval [CI], -0.36 to -0.09; P = 0.001). There was no difference after thyroid cancer patients underwent thyroidectomy (-0.19; 95% CI, -0.47 to 0.10; P = 0.21). A fixed-effect model was used to pool the odds ratio of thyroid cancer and vitamin D deficiency. It showed that the pooled odds ratio from six studies was 1.30 (95% CI, 1.00-1.69; P = 0.05). Subgroup analysis of 25-hydroxyvitamin D levels between different pathologic characteristics in patients with thyroid cancer was summarized, but no statistical differences were determined.

CONCLUSIONS

Lower serum 25-hydroxyvitamin D levels were associated with increased risk for thyroid cancer. On the other hand, vitamin D deficiency may act as a risk factor for thyroid cancer.

Insulin resistance is associated with larger thyroid volume in adults with type 1 diabetes independently from presence of thyroid autoimmunity

To investigate the effect of insulin resistance (IR) on thyroid function, thyroid autoimmunity (AIT) and thyroid volume in type 1 diabetes (T1DM). 100 consecutive patients with T1DM aged 29 (±6) years with diabetes duration 13 (±6) years were included. Exclusion criteria were: history of thyroid disease, current treatment with L-thyroxin or anti-thyroid drugs. Evaluation of thyroid stimulating hormone (TSH), free thyroid hormones and anti-thyroid antibodies was performed. Thyroid volume was measured by ultrasonography. IR was assessed using the estimated glucose disposal rate (eGDR) formula. In the study group 22% of subjects had insulin resistance defined as eGDR lower or equal to 7.5 mg/kg/min. The prevalence of thyroid autoimmunity (positivity for ATPO or ATg or TRAb) in the study group was 37%. There were no significant differences in the concentration of TSH, FT3, FT4, the prevalence of AIT and hypothyroidism between IR and insulin sensitive (IS) group. Mean (±SD) thyroid volume was 15.6 (±6.2) mL in patients with IR and 11.7 (±4.7) mL in IS subjects (p = .002). Thyroid volume correlated inversely with eGDR (r = -0.35, p < .001). In a multivariate linear regression model the association between thyroid volume and eGDR was independent of sex, age, duration of diabetes, daily insulin dose, BMI, cigarette smoking, TSH value and presence of thyroid autoimmunity (beta: -0.29, p = .012). Insulin resisance is associated with larger thyroid volume in patients with type 1 diabetes independently of sex, body mass index, TSH value and presence of autoimmune thyroid disease.

Vitamin D, FOXO3a, and Sirtuin1 in Hashimoto's Thyroiditis and Differentiated Thyroid Cancer

Background: Protective effects of vitamin D have been reported in autoimmune and malignant thyroid diseases, though little is known about the underlying mechanism. Sirtuin 1 histon deacethylase (SIRT1) links the vitamin D pathway with regulation of transcription factor FOXO3a, a key player in cell cycle regulation and apoptosis. Aim of the present study was to investigate common single nucleotide polymorphisms (SNP's) in FOXO3a gene in respect to thyroid diseases, as well as to evaluate the hypothesis of Sirtuin1-FOXO3a interaction being a mediator of anti-proliferative vitamin D effects. Methods: The SNP's FOXO3a rs4946936/rs4945816/rs9400239 were genotyped in 257 patients with differentiated thyroid carcinoma (DTC), 139 patients with Hashimoto thyroiditis (HT) and 463 healthy controls (HC). Moreover, T-helper cells of HC and papillary thyroid cancer cell line BCPAP were incubated with 1,25(OH)₂D₃ and/or SIRT1 inhibitor Ex-527 in order to elucidate SIRT1- dependent vitamin D effects on cell proliferation and FOXO3a gene expression in vitro. Results: Patients with DTC tended to carry more often allele C in FOXO3a rs4946936 in comparison to HC (p_corrected = p_c = 0.08). FOXO3a rs9400239T and rs4945816C was more frequent in HT in comparison to HC (p_c = 0.02 and p_c = 0.01, respectively). In both DTC and HT, we could not find a correlation of FOXO3a SNP's with vitamin D status. However, on in vitro level, 1,25(OH)₂D₃ showed an anti-proliferative effect in both T-helper cells and BCPAP, that was blocked by SIRT1 inhibition (T-helper cells: p = 0.0059, BCPAP: p = 0.04) and accompanied by elevated FOXO3a gene expression in T-helper cells (p = 0.05). Conclusions: FOXO3a rs9400239T and rs4945816C may constitute risk factors for HT, independent of the vitamin D status.This indicates the implication of FOXO3a in pathogenesis of autoimmune thyroid diseases. The dependency of anti-proliferative vitamin D effects on SIRT1 activity further suggests a key role of vitamin D-SIRT1-FOXO3a axis for protective vitamin D effects.

Serum ghrelin levels in papillary thyroid carcinoma

OBJECTIVE

Ghrelin plays a role in several processes of cancer progression, and numerous cancer types express ghrelin and its receptor. We aimed to investigate serum levels of ghrelin in patients with papillary thyroid carcinoma (PTC) and its association with the prognostic factors in PTC.

MATERIALS AND METHODS

We enrolled 54 patients with thyroid cancer (7 male, 47 female) and 24 healthy controls (6 male, 18 female) in the study. We compared demographic, anthropometric, and biochemical data, and serum ghrelin levels between the groups. Serum ghrelin levels were measured using as enzyme-linked immunosorbent assay.

RESULTS

Ghrelin levels were similar between the groups, but plasma ghrelin levels were significantly higher in tumors larger than 1 cm diameter compared with papillary microcarcinomas. Serum ghrelin levels also correlated with tumor size (r = 0.499; p < 0.001). Body mass index, thyroid-stimulating hormone, and HOMA-IR levels were similar between the groups. There were no statistically significant differences regarding average age and other prognostic parameters including lymph node invasion, capsule invasion, multifocality and surgical border invasion between patients with microcarcinoma and tumors larger than 1 cm.

CONCLUSION

In our study, no significant difference in serum ghrelin levels was determined between patients with papillary thyroid cancer and healthy controls however, serum ghrelin levels were higher in tumors larger than 1 cm compared to in those with thyroid papillary microcarcinoma.

The Role of Vitamin D in Thyroid Diseases

The main role of vitamin D is regulating bone metabolism and calcium and phosphorus homeostasis. Over the past few decades, the importance of vitamin D in non-skeletal actions has been studied, including the role of vitamin D in autoimmune diseases, metabolic syndromes, cardiovascular disease, cancers, and all-cause mortality. Recent evidence has demonstrated an association between low vitamin D status and autoimmune thyroid diseases such as Hashimoto’s thyroiditis and Graves’ disease, and impaired vitamin D signaling has been reported in thyroid cancers. This review will focus on recent data on the possible role of vitamin D in thyroid diseases, including autoimmune thyroid diseases and thyroid cancers.

Sunshine vitamin and thyroid

Vitamin D exerts its canonical roles on the musculoskeletal system and in the calcium/phosphorus homeostasis. In the last years, increasing evidences suggested several extra-skeletal actions of this hormone, indicating that vitamin D may produce effects in almost all the body tissues. These are mediated by the presence of vitamin D receptor (VDR) and thanks to the presence of the 1-α-hydroxylase, the protein that converts the 25-hydroxyvitamin (calcidiol) to the active form 1,25-dihydroxyvitamin (calcitriol). Several studies evaluated the possible role of vitamin D in the pathogenesis of thyroid diseases, and this review will focus on the available data of the literature evaluating the association between vitamin D and thyroid function, vitamin D and autoimmune thyroid diseases, including Hashimoto's thyroiditis, Graves' disease and post-partum thyroiditis, and vitamin D and thyroid cancer.

Frequency of nodular goiter and autoimmune thyroid disease and association of these disorders with insulin resistance in polycystic ovary syndrome

Objective:

Polycystic ovary syndrome (PCOS) is a frequent endocrine disease in women. Nodular goiter and autoimmune thyroid disease (AITD) are endocrinologic abnormalities that have high prevalence. The purpose of our study was to detect the prevalence of AITD and nodular goiter in patients with PCOS and investigate whether PCOS-related hormones and metabolic factors affect these thyroid disorders.

Material and Methods:

Ninety-seven women with PCOS and 71 healthy female volunteers were recruited into the study. Serum-free thyroxine, thyroid-stimulating hormone, anti-thyroperoxidase antibody and anti-thyroglobulin antibody levels were evaluated. Thyroid volume (TV) was calculated using ultrasonography.

Results:

The body mass index (BMI), Waist/Hip ratio, homeostasis model assessment insulin resistance (HOMA-IR), fasting blood glucose, triglyceride and low-density lipoproteins, and fasting insulin were significantly higher in the PCOS group (p<.05). The control group had significantly higher serum high density lipoprotein cholesterol results (p=.005). The mean TV was 11.4±4.7 mL in the PCOS group and 9.9±2.8 mL in the controls (p=.022). Twenty-nine patients with PCOS (29/97; 29.9%) had thyroid nodules, whereas only eleven control subjects had thyroid nodules (11/71; 15.5%) (p=.043). The frequency of AITD was significantly higher in the PCOS group (p=.001). A statistically significant relationship was found between TV and age, fasting glucose, HOMA-IR, BMI, and fasting insulin (p<.05). Participants with thyroid nodules were older and had higher fasting glucose, BMI, fasting insulin, and HOMA-IR values compared with those without thyroid nodules (p<.05).

Conclusion:

We demonstrated that TV and frequency of nodular goiter were increased in patients with PCOS. This result was related with insulin resistance. Therefore, we recommend that patients with PCOS must be investigated for the development of nodular goiter and AITD.

Serum vitamin D3 levels are not associated with thyroid cancer prevalence in euthyroid subjects without autoimmune thyroid disease

BACKGROUND/AIMS

Previous studies have suggested that elevated serum vitamin D levels might protect against thyroid cancer. Elevated serum thyroid stimulating hormone levels and autoimmune thyroid disease (AITD) are suggested to be thyroid cancer promoting factors but have not been well controlled in previous studies. We designed the present study to evaluate whether serum vitamin D levels are associated with thyroid cancer in euthyroid patients with no clinical evidence of AITD.

METHODS

This cross-sectional study included subjects who underwent routine health check-ups, including serum 25-hydroxy vitamin D3 (25(OH)D3) levels, anti-thyroid peroxidase antibody (TPO-Ab), and thyroid ultrasonography (US). Inclusion criteria were euthyroid, negative TPO-Ab, and no evidence of AITD by US findings. Thyroid cancer diagnoses were based on fine needle aspiration cytology and/or postsurgical histopathological findings.

RESULTS

We enrolled 5,186 subjects (64% male, 37% female) in this study, including 53 patients (1%) with a diagnosis of thyroid cancer (33 males, 20 females). Mean 25(OH)D3 levels were similar between the thyroid cancer and control groups (p = 0.20). Subgroup analysis according to sex or seasonal variation also revealed no differences in 25(OH)D3 levels between the two groups. Based on the levels of 25(OH)D3, there was no significant difference in the prevalence of thyroid cancer; the prevalence was 0.71%, 0.94%, 1.40%, and 0.82% in the deficient, insufficient, sufficient, and excess groups, respectively (p = 0.64).

CONCLUSIONS

The levels of serum 25(OH)D3 are not associated with thyroid cancer prevalence in euthyroid subjects with no clinical evidence of AITD.

25-Hydroxyvitamin D and TSH as Risk Factors or Prognostic Markers in Thyroid Carcinoma

Objective

The increasing incidence of thyroid nodules demands identification of risk factors for malignant disease. Several studies suggested the association of higher TSH levels with cancer, but influence of 25-hydroxyvitamin D (25OHD) is controversial. This study aimed to identify the relationship of thyroid cancer with higher TSH levels and hypovitaminosis D and to evaluate their influence on prognostic characteristics of papillary thyroid carcinomas (PTC).

Methods

We retrospectively evaluated 433 patients submitted to thyroidectomy for thyroid nodules. Patients were categorized according to quartiles of TSH and 25OHD levels. Clinicopathological features were analyzed.

Results

Subjects with thyroid carcinomas were more frequently male and younger compared to those with benign disease. Their median TSH levels were higher and adjusted odds-ratio (OR) for cancer in the highest-quartile of TSH (> 2.4 mUI/mL) was 2.36 (1.36–4.09). Although vitamin D deficiency/insufficiency was prevalent in our cohort (84%), no significant differences in 25OHD levels or quartile distribution were observed between benign and malignant cases. Among 187 patients with PTC, analyses of prognostic features revealed increased risk of lymph nodes metastases for subjects with highest-quartile TSH levels (OR = 3.7, p = 0.029). Decreased 25OHD levels were not overtly associated with poor prognosis in PTC.

Conclusions

In this cross-sectional cohort, higher TSH levels increased the risk of cancer in thyroid nodules and influenced its prognosis, particularly favoring lymph nodes metastases. On the other hand, no association was found between 25OHD levels and thyroid carcinoma risk or prognosis, suggesting that serum 25OHD determination may not contribute to risk assessment workup of thyroid nodules.

Follicular variant of papillary thyroid cancer in Alström syndrome

Alström syndrome (AS) is an autosomal recessive disorder, characterized by cone-rod dystrophy, sensorineural hearing loss, obesity, hyperinsulinemia with insulin resistance, type 2 diabetes mellitus and progressive pulmonary, hepatic and renal dysfunction. AS is caused by mutations in the ALMS1 gene, located on the short arm of chromosome 2. We report a 35-year-old woman with known history of AS, who developed a follicular variant of papillary thyroid carcinoma. To our knowledge this is the first association of AS with thyroid malignancy, among the approximately 450 cases reported since the first description of the syndrome. We conclude that papillary thyroid carcinoma should be considered in the differential diagnosis of thyroid nodules in patients with AS.

High prevalence of papillary thyroid cancer in Korean women with insulin resistance

BACKGROUND

The purpose of this study was to determine if hyperinsulinemia and/or insulin resistance are/is associated with the prevalence of papillary thyroid cancer (PTC) in Korean women.

METHODS

This study included 735 female patients with PTC and 537 female non-PTC control subjects. Multiple logistic regression analysis was performed to evaluate the associations between hyperinsulinemia/insulin resistance and the occurrence of PTC.

RESULTS

The prevalence of PTC was significantly correlated with increased insulin, glucose levels, and a high homeostasis model of assessment-insulin resistance (HOMA-IR). The multivariate adjusted odds ratios for the prevalence of PTC in the highest quartile groups for insulin, glucose, and HOMA-IR were 2.88, 9.32, and 4.07 (all p < .001), respectively, compared with the lowest quartile groups. Pathological analyses revealed that increased serum glucose, insulin levels, and a higher HOMA-IR were associated with the multifocality of PTC.

CONCLUSION

Hyperinsulinemia and/or insulin resistance may be associated with the development of PTC, but not disease severity in Korean women.

Insights into genetic and epigenetic determinants with impact on vitamin d signaling and cancer association studies: the case of thyroid cancer

Vitamin D is a key regulator of calcium metabolism and has been implicated as a cancer preventive agent. However, clinical studies have revealed conflicting results on its cancer preventive properties, attributed in part to multiple metabolic and regulatory factors susceptible to affect individual responses to exogenous vitamin D. Vitamin D is obtained from dietary sources and sun exposure, which depends on numerous parameters such as skin type, latitude, and lifestyle factors. Focusing on thyroid cancer (TC), we document that genetic and epigenetic determinants can greatly impact individual response to vitamin D and may outweigh the classical clinical correlative studies that focus on sun exposure/dietary intake factors. In particular, genetic determinants innate to host intrinsic metabolic pathways such as highly polymorphic cytochromes P450s responsible for the metabolic activation of vitamin D are expressed in many organs, including the thyroid gland and can impact vitamin D interaction with its nuclear receptor (VDR) in thyroid tissue. Moreover, downstream regulatory pathways in vitamin D signaling as well as VDR are also subject to wide genetic variability among human populations as shown by genome-wide studies. These genetic variations in multiple components of vitamin D pathways are critical determinants for the revaluation of the potential preventive and anticancer properties of vitamin D in TC.

Investigation of insulin resistance gene polymorphisms in patients with differentiated thyroid cancer

We aimed to investigate insulin receptor substrate-1 (IRS-1), insulin receptor substrate-2 (IRS-2), insulin-like growth factor binding protein-3 (IGFBP-3) genotypes, which are thought to be involved in the pathogenesis of many solid tumors and have thus far not been studied in patients with differentiated thyroid cancer (DTC). The study consisted of 93 patients diagnosed with DTC (79 females, 14 males) and 111 healthy control subjects (63 females, 48 males). The anthropometric measurements, lipid profiles, thyroid function tests and homeostatic model assessment (HOMA) as an indicator of insulin resistance (IR) of all patients were recorded. In addition IRS-1, IRS-2 and IGFBP-3 gene polymorphisms were determined by using polymerase chain reaction and restriction fragment length polymorphism. Hardy-Weinberg equilibrium was tested for each gene polymorphisms, and genetic effects were evaluated by the Chi Square test and multiple logistic regression. Homeostasis model assessment of insulin resistance (HOMA-IR), body mass index, waist circumference and serum total cholesterol levels were significantly higher in patients with DTC than in the control group. There was no difference between the two groups with respect to IRS-1, IRS-2 and IGFBP-3 gene polymorphisms. In addition, these gene polymorphisms were found to have no effect on lymph node metastases or tumor staging. While, obesity and increased HOMA-IR may be risk factors in DTC development, we suggest that IRS-1, IRS-2 and IGFBP-3 gene polymorphisms do not play an important role in pathogenesis of DTC.