Decreased 1-25 dihydroxyvitamin D3 concentration in peripheral blood serum of patients with thyroid cancer

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.

The association between vitamin D supplementation and the long-term prognosis of differentiated thyroid cancer patients: a retrospective observational cohort study with propensity score matching

Objective

Benefits of vitamin D in various cancers have been reported, but its effects on differentiated thyroid cancer (DTC) have not been established. We aimed to analyze the effect of vitamin D supplementation on the prognosis of DTC.

Methods

A retrospective observational cohort study was conducted on 9,739 DTC patients who underwent thyroidectomy from January 1997 to December 2016. Mortality was classified as all-cause, cancer-related, or thyroid cancer-related. Patients were divided into the "VD group" (supplemented with vitamin D) and the "control group" (without vitamin D supplementation). Propensity score matching was performed in a 1:1 ratio according to age, sex, tumor size, extrathyroidal extension (ETE), and lymph node metastasis (LNM) status, and 3,238 patients were assigned to each group. Kaplan-Meier curves, log-rank test and Cox proportional hazards regression analysis were performed.

Results

The follow-up period was 10.7 ± 4.2 years. Clinicopathological variables between two groups were similar except for all-cause (p<0.001) and total cancer death (p=0.001). From the Kaplan-Meier curve and log-rank test, "VD group" had significantly favorable all-cause (p<0.001) and total cancer mortality (p=0.003), but similar thyroid cancer mortality (p=0.23). In Cox regression, vitamin D intake reduced the risk of all-cause (hazard ratio [HR], 0.617, p=0.001) and total cancer mortality (HR, 0.668, p=0.016) but had no effect on thyroid cancer mortality.

Discussion/conclusion

Vitamin D supplementation was positively associated with all-cause and total cancer mortality in DTC and might be a modifiable prognostic factor for improved survival. Further research will be needed to clarify the effect of vitamin D supplementation on DTC.

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.

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.

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.

The Controversial Role of Vitamin D in Thyroid Cancer Prevention

Thyroid cancer is the most common endocrine malignancy and exhibits rising incidence. Annual incidence varies by sex, age, and geographical location. It has been reported that impairment of vitamin D signalling promotes thyroid cancer progression. Recent studies have shown that vitamin D, a fat-soluble vitamin that acts as both a nutrient and a hormone, may have utility in the prevention of autoimmune thyroid-related diseases. However, the precise role of vitamin D in the pathobiology of thyroid cancer is controversial. Previous studies have suggested that elevated serum vitamin D levels have a protective role in thyroid cancer. However, there is also evidence demonstrating no inverse relationship between vitamin D levels and the occurrence of thyroid cancer. Furthermore, recent data provide evidence that circulating vitamin D concentration is inversely correlated with disease aggressiveness and poor prognosis, while evidence of an association with tumour initiation remains weak. Nevertheless, a variety of data support an anti-tumorigenic role of vitamin D and its potential utility as a secondary chemopreventive agent. In this review, we highlighted recent findings regarding the association of vitamin D status with the risk of thyroid cancer, prognosis, potential mechanisms, and possible utility as a chemopreventive agent.

Simultaneous determination of vitamin D metabolites 25(OH)D3 and 1α,25(OH)2D3 in human plasma using liquid chromatography tandem mass spectrometry

•

LC-MS/MS method development and optimization for simultaneous determination of 25(OH)D₃ and 1α,25(OH)₂D₃ in human plasma.

•

Lowest concentration of 25(OH)D₃ and 1α,25(OH)₂D₃ was 1000 and 20 pg/mL, respectively.

•

The validated method was applied to a pharmacokinetic study in humans.

Background

Although measurement of 25(OH)D₃ is a routine analytical method to determine plasma vitamin D status, 1α,25(OH)₂D₃ is the biologically active form. Hence, simultaneous measurement of 25(OH)D₃ and 1α,25(OH)₂D₃ could provide better insight into vitamin D status and pharmacokinetics. However, 1α,25(OH)₂D₃ has a low plasma concentration, making its quantification challenging for most analytical techniques. Here, we demonstrate use of liquid chromatography tandem mass spectrometry (LC-MSMS) for the development of a simple and rapid method for the simultaneous quantification of 25(OH)D₃ and 1α,25(OH)₂D₃.

Methods

Samples were purified from 250 µL human plasma. Chromatography was performed on an analytical column, under gradient conditions using a mobile phase consisting of methanol-lithium acetate. The mass detector was operated in positive multiple reaction monitoring mode. The established method was validated according to the guidance issued by ICH and FDA. Furthermore, a clinical study was performed using this method to detect the plasma concentrations of 1α,25(OH)₂D₃ after oral administration of calcitriol.

Results and conclusion

The method was acceptably linear over the concentration ranges of 20–1200 pg/mL for 1α,25(OH)₂D₃ and 1–60 ng/mL for 25(OH)D₃, respectively, with correlation coefficients of r² > 0.993. Both the inter-assay and intra-assay precision was < 15%, and the analytical recoveries were within 100% ± 10%, with no significant matrix effect or carryover. Thereby, we, provide a facile method for the simultaneous detection of vitamin D metabolites in plasma.

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.

Correlation between Pre-Operative 25-Hydroxyvitamin D Levels and Poor Prognostic Factors for Papillary Thyroid Cancer

PURPOSE

To evaluate the relationship between pre-operative 25-hydroxyvitamin D (25 (OH) D) levels and poor prognostic factors for papillary thyroid cancer (PTC).

METHODS

A total of 1161 patients diagnosed with PTC were analyzed retrospectively. The patients were categorized .based on their pre-operative 25 (OH) D levels into three groups: the severe vitamin D deficiency (VDD) group (25 (OH) D < 10 ng/mL), moderate VDD group (20 ng/mL > 25 (OH) D ≥ 10 ng/mL), and control group (25(OH)D ≥ 20 ng/mL) Differences in the demographic and clinicopathological characteristics among the three groups were analyzed. Linear and logistic regression analyses were also performed to determine the effect of 25 (OH) D levels on the established poor prognostic factors for PTC.

RESULTS

We observed a negative correlation between 25 (OH) D levels and tumor size (r = -0.067, P = 0.049). Severe VDD and moderate VDD were independently associated with lymph node metastasis and distant metastasis diagnosed during surgery (P = 0.00, odds ratio (OR) = 4.11; P = 0.00, OR = 3.33, respectively). After adjusting parameters such as sex, age, body mass index, and thyroid-stimulating hormone (TSH) levels, severe VDD and moderate VDD were found to be closely associated with advanced cancer stage (stage III or IV) (P = 0.018, OR = 3.02; P = 0.041, OR = 3.60, respectively). Additionally, a significant correlation (P = 0.007) was observed between the pre-operative 25 (OH) D and TSH levels.

CONCLUSION

25 (OH) D levels were significantly associated with certain poor prognostic factors for PTC, including larger tumor diameter and the occurrence of lymph node metastasis. More prospective studies are needed to evaluate whether the assessment and supplementation of vitamin D contributes to the pre-operative management of patients with PTC.

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.

Vitamin D as a Potential Therapeutic Option in Cancer Treatment: Is There a Role for Chemoprevention?

BACKGROUND

Vitamin D (Vit D) serves as a precursor to the potent steroid hormone calcitriol, which regulates numerous genes that control homeostasis, epithelial cell differentiation, proliferation, and apoptosis. Low level of Vit D is implicated in the development and progression of several diseases including bone fractures, cardiovascular disease, diabetes mellitus, and cancers. The present review highlights the role of vitamin D in cancer with a particular emphasis on genetic variants related to Vit D metabolism as well as clinical trials of Vit D supplementation as a potential therapeutic option in the treatment of cancer patients.

METHODS

Data were collected following an electronic search in the Web of Science, Medline, PubMed, and Scopus databases by using some keywords such as "cancer", "tumor", "malignancy", "vitamin D", "cholecalciferol" and "calcitriol".

RESULTS

The collected evidence from the studies revealed a consistent and strong association between Vit D status and cancer risk and survival. The associations between Vit D-related genetic variants and cancer survival support the hypothesis that Vit D may affect cancer outcomes. The mechanisms whereby Vit D reduces cancer risk and increases survival are regulation of cellular differentiation, proliferation and apoptosis as well as decreased angiogenesis in tumor microenvironment and inhibition of metastasis.

CONCLUSION

There is a paucity of evidence-based recommendations for the optimal 25(OH)D levels in patients with cancer and the role of Vit D supplementation for primary or secondary prevention of cancer. Well-designed and sufficiently powered randomized clinical trials are necessary to assess the clinical application of Vit D in enhancing the clinical efficacy of standard and adjuvant chemotherapy regimens.

Association of Low Serum 25OHD Levels with Abnormal Bone Microarchitecture in Well-Differentiated Thyroid Cancer

The association of low levels of 25 hydroxyvitamin D (25OHD) with papillary thyroid cancer (PTC) is being studied, as to whether it is a risk factor or as a coincidental one. This study aimed to evaluate serum levels of deficiency, insufficiency, and sufficiency of 25OHD in PTC and its relationship with the trabecular bone score (TBS) and bone mineral density (BMD). This study includes 134 postmenopausal women with PTC, followed for 10 years. BMD was measured with DXA Hologic QDR 4500, and TBS with Med-Imaps iNsight2.0 Software. Mean serum 25OHD was 23.09 ± 7.9 ng/mL and deficiency, insufficiency, and sufficiency levels were 15.64 ± 2.9, 25.27 ± 2.7, and 34.7 ng/mL, respectively. Parathyroid hormone (PTH) and bone alkaline phosphatase (BAP) were higher in deficiency (57.65 ± 22.6 ng/mL; 29.5 ± 14 U/L) and in insufficiency (45.88 ± 19.8 ng/mL; 23.47 ± 8.8 U/L) compared with sufficiency of 25OHD (47.13 ± 16 and 22.14± 9.7 ng/mL) (p = 0.062 and p = 0.0440, respectively). TBS was lower in patients with 25OHD < 20 ng/mL (1.24 ± 0.13) compared with between 20-29 (1.27 ± 0.13, p < 0.05) and 30 ng/mL (1.31 ± 0.11, p < 0.01). We found low TBS in patients with PTC and long-term follow-up associated with low serum 25OHD levels, not associated with cancer stage, or accumulative iodine radioactive dose. Low 25OHD associated with deleterious bone quality in patients with PTC should be restored for the prevention of fractures.

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.

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.

Decreased apolipoprotein A4 and increased complement component 3 as potential markers for papillary thyroid carcinoma: A proteomic study

BACKGROUND:

Thyroid carcinomas have comprised the fastest rising incidence of cancer in the past decade. Currently, the diagnosis of thyroid tumors is performed by the fine-needle aspiration biopsy (FNAB) method, which still holds some challenges and limitations, mostly in discriminating malignant and benign lesions. Therefore, the development of molecular markers to distinguish between these lesion types are in progress.

METHODS:

A 2D-PAGE separation of proteins was performed followed by tandem mass spectrometry with the aim of discovering potential serum protein markers for papillary thyroid carcinoma and multinodular goiter. Protein-protein interaction network analysis revealed the most important pathways involved in the progression of papillary thyroid cancer. The enzyme-linked immunosorbent assay method was used to confirm a part of the results.

RESULTS:

The significantly altered proteins included C3, C4A, GC, HP, TTR, APOA4, APOH, ORM2, KRT10, AHSG, IGKV3-20, and IGKC. We also confirmed that increased complement component 3 and decreased apolipoprotein A4 occurred in papillary thyroid cancer. Network investigations demonstrated that complement activation cascades and PPAR signaling might play a role in the pathogenesis of thyroid cancer.

CONCLUSION:

The results demonstrated that serum proteomics could serve as a viable method for proposing novel potential markers for thyroid tumors. Surely, further research must be performed in larger cohorts to validate the results.

CYP24A1 depletion facilitates the antitumor effect of vitamin D3 on thyroid cancer cells

It has been demonstrated that 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1) is a key enzyme that neutralizes vitamin D activity, which may have an anti-tumor effect. Therefore, the aim of the current study was to explore the effect of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25-D3) on thyroid cancer cells following the downregulation of CYP24A1. A Cell Counting Kit-8 assay identified that CYP24A1 knockdown enhanced the anti-proliferative effects of 1,25-D3 on thyroid cancer cells. Furthermore, the results of the scratch wound and Transwell assays indicated that CYP24A1 knockdown enhanced the inhibitory effect of 1,25-D3 on cell migration. The results from reverse transcription-quantitative polymerase chain reaction and western blot analysis indicated that treatment with 1,25-D3 and CYP24A1 knockdown synergistically enhanced the expression of the epithelial-related gene E-cadherin and decreased the expression of the mesenchymal-related genes N-cadherin and vimentin. Following CYP24A1 knockdown and treatment with 1,25-D3, the expression of matrix metalloproteinase 2 and metalloproteinase inhibitor 1 were significantly decreased and increased, respectively, compared with the group that underwent treatment with 25-D3 alone. Furthermore, protein kinase B (Akt) and β-catenin activity was significantly decreased by this synergetic effect compared with the group that underwent treatment with 1,25-D3 alone. The results of the current study suggest that CYP24A1 knockdown contributes to the anti-tumor effect of 1,25-D3 and that this effect may be due to deactivation of the Akt and β-catenin signaling pathways. Therefore, CYP24A1 knockdown and 1,25-D3 treatment may be used synergistically as a novel therapeutic strategy to treat patients with thyroid cancer.

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.

Potential Use of 1-25-dihydroxyvitamin D in the Diagnosis and Treatment of Papillary Thyroid Cancer

BACKGROUND Low levels of 1-25-dihydroxyvitamin D3 [1,25(OH)2D3] in serum may be a risk factor for several tumor types. Also, high cathelicidin antimicrobial peptide (CAMP) expression is regarded to be important against tumor progression. We evaluated the potential importance of 1,25(OH)2D3 in the diagnosis and treatment of papillary thyroid cancer (PTC). MATERIAL AND METHODS The preoperative serum level of 1,25(OH)2D3 was measured using a double-antibody sandwich enzyme-linked immunosorbent assay. Vitamin D3 receptor (VDR) expression was detected by streptavidin-peroxidase immunohistochemical staining in PTC specimens. Receiver operating characteristic (ROC) curves were created to assess the diagnostic value of 1,25(OH)2D3. The effect of 1,25(OH)2D3 on the proliferation and apoptosis of PTC cell lines were studied by Cell Counting Kit (CCK)-8 assay and Annexin V/propidium iodide staining, respectively. CAMP expression was measured by qRT-PCR and western blotting. Short interfering RNAs were used to reduce CAMP expression in PTC cell lines. RESULTS The preoperative serum level of 1,25(OH)2D3 in PTC was obviously lower than that in nodular goiter (NG) (P<0.05). The ROC curve suggested that 1,25(OH)2D3 might serve as a potential diagnostic value at a cutoff of 20.13 pg/mL, The VDR showed higher expression in PTC than in paired adjacent non-cancerous tissue. 1,25(OH)2D3 inhibited the proliferation and induced the apoptosis of PTC cells, and increased CAMP expression significantly, whereas CAMP knockdown demonstrated opposite effects. CONCLUSIONS 1,25(OH)2D3 may be a new, potential biomarker for the identification of PTC and NG. It may also become 1,25(OH)2D3 may a potential target for drug action to treat PTC through CAMP.

Vitamin D Deficiency Associated with Differentiated Thyroid Carcinoma: A Case- Control Study

Objective:

In recent decades, the incidence of thyroid cancer has increased throughout the world. It is unclear whether factors such as vitamin D deficiency may have been involved in this increase. The present case-control study was conducted to examine any association between Vitamin D deficiency and thyroid cancers.

Methods:

The study was conducted on 85 patients with differentiated thyroid cancer diagnosed based on fine needle aspiration biopsy as the case group and 85 healthy controls. Serum levels of vitamin D were evaluated before thyroidectomy. For each patient in the case group, one healthy euthyroid person without any thyroid nodules from the general population matched based on season, sex, age (± 1 year) and BMI (± 1) was selected. Finally, 85 pairs were obtained considering inclusion and exclusion criteria. Thyroid function, thyroid antibodies and serum vitamin D were assessed and thyroid sonography was performed in all participants.

Results:

In the patient group, 72 (85%) were female and 13 (15%) were male. The mean (SD) serum vitamin D level was 8.00 (±3.7) in patient group, as compared to 13.4 (±7.90) in the control group, the difference being significant (OR: 6, 95 %CI: 1.02-113.3; P=0.046).

Conclusion:

A significant association was noted between vitamin D deficiency and differentiated thyroid cancer. Further studies with a prospective design are necessary to further define the roles of this factor.

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.

Micronutrient status (calcium, zinc, vitamins D and E) in patients with medullary thyroid carcinoma: A cross-sectional study

OBJECTIVE

The aim of this study was to evaluate the micronutrient status of Iranian patients with medullary thyroid carcinoma (MTC) and to analyze potential relationships with respect to MTC risk.

METHODS

This was a cross-sectional study (Tehran Thyroid Cancer Survey 2015-2016). We measured and compared preoperative serum calcium, zinc, and vitamins D and E in patients with MTC and healthy controls. Forty cases with MTC and 40 (age-, sex-, and body mass index-matched) healthy controls voluntarily participated in the project.

RESULTS

Serum calcium, zinc, and vitamin D and E concentrations were lower in the patients with cancer (P_Ca < 0.001, P_Zn = 0.01, P_D = 0.056, P_E = 0.002) than in the healthy controls. We found that serum calcium remarkably associated with enhanced risk for thyroid cancer (odds ratio [OR], 6.5; P = 0.001). Likewise, serum vitamin E was linked to the risk for cancer (OR, 1.31; P = 0.056). Moreover, serum zinc was correlated with vitamin E and calcium (r = +0.23; P = 0.04 and r = +0.25, P = 0.03; respectively). We also observed a correlation between calcium and vitamin E (r = +0.27; P = 0.02).

CONCLUSIONS

A multiple-micronutrient decrease was confirmed in patients with MTC. A low serum calcium level was a potent risk factor for MTC. Findings from the present study suggest that dietary intake and/or supplementation of micronutrients, especially calcium and vitamin E, may be beneficial in reducing the risk for thyroid cancer.

Cyp24a1 Attenuation Limits Progression of BrafV600E -Induced Papillary Thyroid Cancer Cells and Sensitizes Them to BRAFV600E Inhibitor PLX4720

CYP24A1, the primary inactivating enzyme for vitamin D, is often overexpressed in human cancers, potentially neutralizing the antitumor effects of calcitriol, the active form of vitamin D. However, it is unclear whether CYP24A1 expression serves as a functional contributor versus only a biomarker for tumor progression. In this study, we investigated the role of CYP24A1 on malignant progression of a murine model of Braf^V600E -induced papillary thyroid cancer (PTC). Mice harboring wild-type Cyp24a1 (BVE^Cyp24a1-wt) developed PTC at 5 weeks of age. Mice harboring a homozygous deletion of Cyp24a1 (BVE^Cyp24a1-null) exhibited a 4-fold reduction in tumor growth. Notably, we found the tumorigenic potential of BVE^Cyp24a1-null-derived tumor cells to be nearly abolished in immunocompromised nude mice. This phenotype was associated with downregulation of the MAPK, PI3K/Akt, and TGFβ signaling pathways and a loss of epithelial-mesenchymal transition (EMT) in BVE^Cyp24a1-null cells, associated with downregulation of genes involved in EMT, tumor invasion, and metastasis. While calcitriol treatment did not decrease cell proliferation in BVE^Cyp24a1-null cells, it strengthened antitumor responses to the BRAF^V600E inhibitor PLX4720 in both BVE^Cyp24a1-null and BVE^Cyp24a1-wt cells. Our findings offer direct evidence that Cyp24a1 functions as an oncogene in PTC, where its overexpression activates multiple signaling cascades to promote malignant progression and resistance to PLX4720 treatment. Cancer Res; 77(8); 2161-72. ©2017 AACR.

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.

Prospective Study of Ultraviolet Radiation Exposure and Thyroid Cancer Risk in the United States

Background: Thyroid cancer incidence has tripled in the past three decades, yet relatively few risk factors have been identified. Some studies have suggested that ultraviolet radiation (UVR) may affect thyroid cancer risk.Methods: We conducted a prospective analysis of 44,039 participants in the United States Radiologic Technologists Study (153 thyroid cancer cases) from all 50 states. We examined the association between risk of thyroid cancer and exposure to UVR, estimated by ambient UVR, time outdoors, and a combined variable. Participants reported location of residence and time outdoors during five age periods starting in childhood. Ambient UVR was estimated by linking satellite-based UVR measurements to geocoded residences. We assessed the association of UVR by age and average lifetime UVR with thyroid cancer risk using Cox proportional hazards models, starting at the time of the baseline questionnaire (2003-2005) through 2012-2013.Results: Combined UVR from the latest age period (age 40+) was associated with a decreased risk of thyroid cancer (HR for 4th vs. 1st quartile = 0.56; 95% CI, 0.31-1.02, P_trend = 0.04). This was limited to participants with benign thyroid disease and to those with darker complexions, although we found no evidence of effect modification. Thyroid cancer risk was unrelated to all metrics of UVR in earlier age periods and for average lifetime exposure.Conclusions: Recent UVR exposure was associated with a decreased risk of thyroid cancer. This association appeared to be modified by benign thyroid disease and skin complexion.Impact: UVR exposure may be associated with a decreased risk of thyroid cancer. Cancer Epidemiol Biomarkers Prev; 26(5); 684-91. ©2016 AACR.

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.

Vitamin D and thyroid diseases

In this review we summarize recent opinions on the possible role of vitamin D in the risk of thyroid diseases development. It may be concluded from the available data that vitamin D deficiency, particularly levels below 12.5 ng/ml should be considered as an additional, but important risk factor for development of thyroid autoimmunity, both chronic autoimmune thyroiditis and Graves' disease. A higher risk of Graves' disease development is also associated with several polymorphisms in the gene encoding for vitamin D binding protein and for the specific receptor of active form of vitamin D - 1,25-(OH)(2)D(3) in the respective target cells. Important for development of thyroid cancer appeared polymorphisms of genes encoding for vitamin D receptors and of genes encoding for the participating hydroxylating enzymes in thyroid tissue, leading to a diminished local 1,25-(OH)(2)D(3) formation capacity with following alteration of antiproliferatory, antiapoptotic and prodifferentiating efficacy of the latter. Whether supplementation with high doses of vitamin D or its analogues possesses preventive or therapeutic effect is an object of intensive studies.

1,25 dihydroxyvitamin D3 inhibits the proliferation of thyroid cancer stem-like cells via cell cycle arrest

BACKGROUND

An anti-proliferative effect of vitamin D has been reported in different carcinomas, including thyroid cancer. Cancer stem cells (CSCs), a very small fraction of cancer cells, are widely believed to be responsible for cancer initiation, relapse and metastasis.

OBJECTIVES

We addressed the question as to whether CSCs derived from the anaplastic thyroid carcinoma cell lines SW1736, C643, HTh74 and its doxorubicin- resistant subline HTh74R are also a target of vitamin D action.

METHODS

The effect of calcitriol on growth of HTh74, HTh74R, SW1736 and C643 cell lines was investigated by cell viability assays. In stem-enriched cells derived from thyro-spheres cell cycle analysis and apoptotic assays were performed. Furthermore, the role of calcitriol in the formation of cancer thyro-spheres and its putative differentiation-inducing effect were analysed.

RESULTS

CSCs isolated as thyro-spheres from all the four anaplastic thyroid carcinoma cells expressed vitamin D receptors as did their parental cells. Calcitriol inhibited proliferation of anaplastic thyroid carcinoma cells with a more pronounced effect on doxorubicin-resistant HTh74R cells, and it significantly reduced the capacity to form stem cell-derived spheres and decreased the size of these spheres that consist of CSCs and their progenitor cells. As revealed by cell cycle analysis, calcitriol induced G2/M phase arrest in thyro-sphere cells derived cells from HTh74, HTh74R and C643 but did not affect apoptosis. Finally, calcitriol altered morphology of CSCs.

CONCLUSION

Calcitriol inhibited the growth of CSCs derived from anaplastic thyroid cancer cells. It may also exert a pro-differentiation effect in thyroid CSCs.

Vitamin D-neutralizing CYP24A1 expression, oncogenic mutation states and histological findings of human papillary thyroid cancer

OBJECTIVE

The aims of the present study were to examine gene and protein expression of the vitamin D-inactivating 24-hyroxylase (CYP24A1) and the activating 1-alpha-hydroxylase (CYP27B1) enzyme in human papillary thyroid cancer (PTC), furthermore, to investigate the association between CYP24A1 expression and numerous clinical, histological parameters and somatic oncogene mutation status of thyroid tumor tissues.

MATERIALS AND METHODS

Gene expression analysis was carried out in 100 Hungarian thyroid samples, both normal and papillary tumor tissue sections of the same patient. The specific mRNA to the selected genes was analyzed by TaqMan probe-based quantitative real-time RT-PCR. The somatic oncogene mutation states of BRAF, NRAS, HRAS and KRAS were also tested.

RESULTS

CYP24A1 mRNA expression was markedly increased in 52 cases (52%) of the examined papillary cancers compared with that of normal thyroid tissue. There was a tendency toward difference in the distribution of high-level CYP24A1 in the PTC accompanied with somatic oncogene mutation. Positive correlation was seen between increased CYP24A1 expression rate and a group of variables reflecting tumor malignity (mainly vascular invasion, lymph node metastasis, tumor size, hypothyreosis) by principal components analysis. No significant alteration was seen in CYP27B1 gene expression between neoplastic and normal tissues.

CONCLUSIONS

A definite alteration was seen in vitamin D3-inactivating CYP24A1 gene activity in PTC compared to their normal tissues on a relatively large patient population. Our findings raise the possibility that CYP24A1 may also directly be involved in thyroid carcinogenesis.

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.

Increased CYP24A1 expression is associated with BRAF(V600E) mutation and advanced stages in papillary thyroid carcinoma

OBJECTIVE

1α, 25(OH)2 D3 (calcitriol), the active form of vitamin D, has been shown to exert antiproliferative effects in many cancers. Overexpression of CYP24A1, the primary vitamin D-inactivating enzyme, is also observed in a variety of human cancers, thus potentially neutralizing the antitumour effect of 1α, 25(OH)2 D3. This study investigates the expression of CYP24A1 and the effect of BRAF(V600E) on its expression in thyroid cancer.

METHODS

We investigated 60 papillary thyroid carcinoma (PTC) specimens for CYP24A1 expression and its association with BRAF mutation and disease progression. CYP24A1 expression was measured by real-time RT-PCR, and BRAF(V600E) mutation was detected by PCR-DNA sequencing analysis. The interaction between BRAF(V600E) and CYP24A1 expression was determined by Western blot analysis and real-time RT-PCR.

RESULTS

CYP24A1 expression was increased in PTC as compared to benign multinodular goitre. The expression was further increased in stage III and IV tumours. There is a strong correlation between CYP24A1 overexpression and BRAF(V600E) mutation (P < 0·01). In thyroid cancer cell lines expressing BRAF(V600E) , CYP24A1 expression was significantly higher when compared to those without BRAF(V600E) expression. BRAF(V600E) transgene expression in CAL62 cell line can induce CYP24A1 expression. Furthermore, BRAF(V600E) inhibitor PLX4720 can significantly down-regulate CYP24A1 expression and enhance the antiproliferative effects of calcitriol in thyroid cancer cell lines.

CONCLUSION

CYP24A1 overexpression is a poor prognostic indicator for PTC and may reflect BRAF(V600E) mutation and MARK activation. The crosstalk between vitamin D and MAPK signalling pathways results in resistance to calcitriol-mediated antitumour effects, and the resistance can be reversed by BRAF(V600E) inhibitor PLX4720.

A pilot study of serum selenium, vitamin D, and thyrotropin concentrations in patients with thyroid cancer

BACKGROUND

Low serum selenium concentrations have been associated with a diagnosis of differentiated thyroid cancer in small studies in selenium deficient areas. We conducted a pilot study to explore associations between selenium concentrations and the diagnosis of thyroid cancer in an area of selenium sufficiency in the United States. As low 25-hydroxyvitamin D concentrations have been associated with several malignancies, we also examined 25-hydroxyvitamin D levels.

METHODS

This study was designed as a pilot study of prediagnostic selenium and 25-hydroxyvitamin D concentrations. We identified 65 euthyroid patients at an academic medical center who were scheduled for thyroidectomy for thyroid cancer, suspicion of thyroid cancer, or nodular disease. Blood samples were obtained two to four weeks prior to thyroidectomy. Samples were analyzed for thyrotropin (TSH), free thyroxine, total triiodothyronine, selenium, and 25 hydroxyvitamin D levels. Concentrations of these analytes were correlated with whether the patient was diagnosed with benign or malignant disease following their thyroidectomy. In patients with thyroid cancer, the concentrations of selenium and 25-hydroxyvitamin D were correlated with various prognostic features.

RESULTS

Although selenium concentrations were not significantly lower in patients with thyroid cancer, serum selenium concentrations were inversely correlated with disease stage (p = 0.011). There were no associations between vitamin D concentration and a diagnosis of thyroid cancer. Within the thyroid cancer patients, vitamin D concentrations were not associated with disease stage or any other prognostic features. In contrast, TSH concentrations were significantly higher in patients with thyroid cancer, and were positively correlated with the number of involved lymph nodes (p = 0.011) and disease stage (p = 0.022).

CONCLUSION

These data confirm the association between serum TSH and advanced thyroid cancer. In addition, they also suggest a potential association between selenium concentrations and higher thyroid cancer stage. No such association was seen for 25-hydroxyvitamin D concentrations. Larger prospective studies will be required to confirm this association. If confirmed, future studies would need to determine if the association is causative in nature. If causation exists, it seems likely that selenium concentrations would influence thyroid cancer development via an independent mechanism from that of TSH.

Vitamin D in thyroid tumorigenesis and development

Besides its classical role in bone and calcium homeostasis, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the active form of vitamin D, has many non-classical effects; antiproliferative, anti-apoptotic and prodifferentiating effects of 1,25(OH)2D3 have been described in several tumour types in preclinical models. This review focuses on the insights gained in the elucidation of the role of 1,25(OH)2D3 in the normal thyroid and in the pathogenesis, progression and treatment of thyroid cancer, the most common endocrine malignancy. An increasing amount of observations points towards a role for impaired 1,25(OH)2D3-VDR signalling in the occurrence and progression of thyroid cancer, and a potential for structural analogues in the multimodal treatment of dedifferentiated iodine-resistant thyroid cancer. A role for vitamin D in thyroid-related autoimmunity is less convincing and needs further study. Altered 1,25(OH)2D3-VDR signalling does not influence normal thyroid development nor thyrocyte function, but does affect C-cell function, at least in rodents. If these findings also apply to humans deserves further study.

Vitamin D3 levels and insulin resistance in papillary thyroid cancer patients

Both insulin resistance (IR) and vitamin D deficiency (VDD) are found to be associated with many cancer types. In this study, we evaluated the presence of IR and VDD in thyroid cancer patients based on controls. Total 344 papillary thyroid cancer and 116 controls were part of the study. Glucose, insulin, homeostasis model analysis-insulin resistance (HOMA-IR) (control group 2.12 ± 0.9 and patient group 3.6 ± 1.1; p < 0.0001), LDL were significantly high; HOMA-S and vitamin D3 levels (control group 19.11 ± 8 and patient group 17 ± 16; p = 0.004) were significantly low in the patient group. Vitamin D deficiency (64/108 in controls vs 166/235; p = 0.026) and insulin resistance (24/108; 115/235; p < 0.0001) were more frequent in papillary thyroid cancer patients. After regression analysis, tumor diameter showed significant association with log-HOMA-IR (B = 0.315; p = 0.017) and log-vitamin D3 (B = 0.207; p = 0.04). Vitamin D deficiency and insulin resistance frequencies show no difference between micro- and macropapillary thyroid cancers. Receiver operating characteristic curve shows the best cutoff point for tumor diameter showing that the presence of lymph node metastasis was 0.65 cm with 81.2 % sensitivity and 52 % specificity. Best cutoff point for the capsular invasion tumor diameter was 0.75 cm with 83.3 % sensitivity and 60.4 % specificity. No difference between follicular and classical type papillary thyroid carcinomas has been yet discovered. As a result, thyroid cancer patients are more insulin resistant and vitamin D3 deficient. Vitamin D3 levels and HOMA-IR index may affect tumor diameter. Tumor size that is lower than 1 cm (0.65-0.75 cm) may be related with capsular invasion and lymph node involvement.

The vitamin d receptor in thyroid development and function

BACKGROUND AND OBJECTIVE

Vitamin D is known to modulate thyroid neoplastic and autoimmune disease. We investigated the role of the vitamin D receptor (VDR) in normal thyroid development and function (thyrocytes and C cells).

METHODS

The thyroid phenotype of VDR knockout mice was studied in comparison to wild-type controls. The mice were fed a normal diet or a calcium-rich diet to circumvent effects induced by hypocalcemia.

RESULTS

Thyroid morphology was unaltered in VDR knockout mice. Also, expression of different parameters of thyrocyte function was comparable (immunohistochemistry). C cell physiology was, however, affected in the absence of the VDR, resulting in increased thyroidal calcitonin expression (immunohistochemistry), paralleled by increased serum calcitonin levels, but only in normocalcemic mice. To study a possible effect of vitamin D status on basal calcitonin levels in humans, serum calcitonin concentrations were compared between vitamin D-deficient and -sufficient patients (serum 25-OH vitamin D3 ≤10 and ≥40 ng/ml, respectively), but no difference was observed.

CONCLUSIONS

In mice, the VDR is redundant for normal thyrocyte function, but not for C cell function, where it mediates the negative control of calcitonin by 1,25-dihydroxyvitamin D3. In patients, vitamin D status does not affect basal serum calcitonin levels. A study in healthy individuals is needed to confirm these findings.

Impaired vitamin D activation and association with CYP24A1 haplotypes in differentiated thyroid carcinoma

BACKGROUND

Common polymorphisms of the vitamin D receptor gene have been reported to affect the risk of breast, colon, prostate, and differentiated thyroid cancer (DTC), but polymorphisms within the genes of vitamin D metabolizing enzymes have not been studied in DTC. The aim of the present study was to investigate the genes for vitamin D enzymes in patients with DTC and healthy controls (HC) as well as the vitamin D (25-hydroxyvitamin D(3), and 1,25-hydroxyvitamin) status.

METHODS

German patients (n=253) with DTC (papillary thyroid carcinoma [PTC] and follicular thyroid carcinoma [FTC]) and HC (n=302) were genotyped for polymorphisms within the vitamin D metabolizing enzymes such as 25-hydroxylase (CYP2R1[rs12794714, rs10741657]), 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1[rs10877012, rs4646536]), and 25-hydroxyvitamin D 24-hydrolase (CYP24A1[rs927650, rs2248137, rs2296241]). Furthermore, the 25-hydroxyvitamin D(3) [25(OH)D(3)] and 1,25-hydroxyvitamin [1,25(OH)(2)D(3)] plasma levels were measured by a radioimmunoassay.

RESULTS

There was no difference in the genotypes; however, the CYP24A1 haplotype analysis showed that rs2248137C/rs2296241A (13.1% vs. 19.1%; corrected p [pc]=0.04) was less frequent in the PTC, whereas the haplotypes rs2248137C/rs2296241G (56.0% vs. 41.9%; pc=0.03), rs927650C/rs2296241G (22.5% vs. 8.4%; pc=1.6×10(-3)), and rs927650C/rs2248137C/rs2296241G (21.1% vs. 7.3%; pc=1.5×10(-3)) were more frequent in the FTC compared with HC. Furthermore, if patients and controls were grouped according to four 25(OH)D(3) categories (severely deficient, deficient, insufficient, and sufficient), then the patients with both DTC subtypes had significantly lower levels of circulating 1,25(OH)(2)D(3), especially in the group with a deficient 25(OH)D(3) status compared with the controls. Although the polymorphisms showed no differences stratified for the four 25(OH)D(3) categories, the activation status by 1,25(OH)(2)D(3) differed significantly depending on the genotypes of the investigated CYP24A1 polymorphisms.

CONCLUSIONS

A higher risk for DTC is conferred by haplotypes within the CYP24A1 gene, low circulating 25(OH)D(3) levels (deficiency), and a reduced conversion to 1,25(OH)(2)D(3). These results confirm and extend previous observations and also support a role of the vitamin D system in the pathogenesis of DTC. How deficient 25(OH)D(3) levels in combination with certain CYP24A1 haplotypes affect vitamin D activation is the subject of future studies.