BsmI but not FokI polymorphism of VDR gene is contributed in breast cancer

Association between vitamin D receptor polymorphism and breast cancer in women: An umbrella review of meta-analyses of observational investigations

This study aimed to conduct an umbrella review of meta-analyses to synthesize the existing evidence regarding the relationship between vitamin D receptor (VDR) polymorphism and breast cancer (BC) risk. A comprehensive search was performed across multiple databases, including Embase, PubMed, Scopus, the Cochrane Database of Systematic Reviews, and the Web of Science. The investigation included 17 meta-analyses for the BsmI polymorphism, 6 for the Cdx2 polymorphism, and 6 for the Poly (A) polymorphism. Among the 119 datasets analyzed, only 6 (5 %) reported statistically significant outcomes (p < 0.05), comprising 2 comparisons for VDR BsmI polymorphism (3 %), 1 for VDR Cdx-2 polymorphism (4 %), and 3 for VDR Poly (A) polymorphism (14 %), across various genetic models. Notably, significant heterogeneity was observed in 82 comparisons, and publication bias was detected in 16 comparisons. Furthermore, a substantial proportion (86 %) of the included studies exhibited critically low methodological quality. In conclusion, our findings suggest that VDR polymorphism (BsmI, Cdx-2, and Poly (A)) is not strongly associated with BC risk in the general population.

Micronutrient Status and Breast Cancer: A Narrative Review

Breast cancer is one of the most common cancers worldwide, at the same time being one of the most prevalent causes of women's death. Many factors such as alcohol, weight fluctuations, or hormonal replacement therapy can potentially contribute to breast cancer development and progression. Another important factor in breast cancer onset includes micronutrient status. In this narrative review, we analyzed 23 micronutrients and their possible influence on breast cancer onset and progression. Further, the aim of this study was to investigate the impact of micronutrient status on the prevention of breast cancer and its possible influence on various therapeutic pathways. We researched meta-analyses, systemic and narrative reviews, retrospective studies, as well as original studies on human and animal models. The results of these studies indicate a possible correlation between the different levels of micronutrients and a decreased risk of breast cancer as well as a better survival rate. However, further studies are necessary to establish adequate doses of supplementation of the chosen micronutrients and the exact mechanisms of micronutrient impact on breast cancer therapy.

VDR, SOD-2, and CYP24A1 Gene Expression in Different Genotypes of BsmI SNP of the Vitamin D Receptor Gene in Individuals with Hypovitaminosis

BACKGROUND

Hypovitaminosis D is a public health problem due to its implications for various diseases. Vitamin D has numerous functions, such as modulating the metabolism of cellular tissues, and it is expressed through the vitamin D receptor (VDR) gene that may influence gene expression modulation, which plays an important role in vitamin D metabolism.

OBJECTIVE

To evaluate the effect of the genotypes of BsmI single nucleotide polymorphism (SNP) of the VDR gene on VDR, SOD2, and CYP24A1 gene expression in individuals with low serum vitamin D levels.

METHODS

This was a cross-sectional analytical study. After signing the informed consent form, individuals were invited to participate and answered a structured questionnaire with identification data. Blood was collected for biochemical analysis, and vitamin D was measured by chemiluminescence; BsmI polymorphism was determined using real-time polymerase chain reaction (PCR) assays with TaqMan allelic discrimination, and gene expression was conducted by qRT-PCR using QuantiFast SYBR® Green PCR Master Mix. Data were analyzed using the SPSS 20.0 software, and differences were considered significant at p < 0.05.

RESULTS

98 individuals with vitamin D ≤ 20 ng/dL were evaluated, and the BsmI SNP of the VDR gene showed CYP24A1 overexpression and low SOD2 expression.

CONCLUSION

BsmI SNP of the VDR gene can modulate the expression of the genes evaluated without interfering with serum levels.

Associations of vitamin D receptor encoding gene variants with premenopausal breast cancer risk

OBJECTIVE

This study evaluates whether vitamin D receptor (VDR) gene variations are associated with premenopausal breast cancer in Pakistani cohorts.

METHODS

Genomic DNA was isolated from 228 breast cancer patients and 500 non-cancer controls. Six polymorphic variants (rs11568820, rs4516035, rs2228570, rs1544410, rs7975232, rs731236) of the VDR gene were genotyped using PCR-RFLP analysis. All statistical analysis was carried out on IBM-SPSS 23 at p-value <.05. Chi-square test and odds ratios (ORs) along with 95% confidence interval (CIs) were applied to evaluate the relationship between VDR gene polymorphisms and breast cancer.

RESULTS

Results showed that the A/A genotype of EcoRV (OR = 2.125, 95% CI = 1.024 to 4.412) and the A/a genotype of Apa1 (OR = 6.094, 95%CI = 4.111 to 9.033) gene polymorphism had an increased risk of premenopausal breast cancer. No associations of the Bsm1 and Taq1 polymorphisms were observed in premenopausal women. Moreover, the Cdx2 GG (OR = 0.34, 95%CI = 0.192-0.602) genotype had a significant protective effect on breast cancer. However, strong LD was existed between Bsm1/Taq1 (D' = 0.757, CI = 0.67-0.82) and Apa1/Taq1 (D' = 0.695, CI = 0.6-0.77). Haplotype analysis showed no association between premenopausal breast cancer and VDR haplotypes.

CONCLUSION

These analyses indicates that the VDR EcoRV A/A and Apa1 A/a genotypes may be risk factors for breast cancer development among premenopausal women.

A Systematic Review of Vitamin D and Fibroids: Pathophysiology, Prevention, and Treatment

Uterine fibroids are the most common tumor of reproductive-age women worldwide and cause significant morbidity in affected women. Vitamin D has emerged as a potential therapy for uterine fibroids based on experimental and epidemiologic evidence. The objective of this systematic review was to evaluate the role of vitamin D in the pathophysiology of uterine fibroids and its efficacy for prevention and treatment of fibroids. A comprehensive search was conducted of Cochrane Library, Embase, PubMed, Scopus, and Web of Science from inception to March 2022. English-language publications that evaluated vitamin D and uterine fibroids in humans, whether experimental or clinical, were considered. The search yielded 960 publications, and 89 publications met inclusion criteria: 23 preclinical studies, 25 clinical studies, and 41 review articles. Preclinical studies indicated that the vitamin D receptor was decreased in fibroid cells. Vitamin D treatment of fibroid cells decreased proliferation, extracellular matrix protein expression, and Wnt/β-catenin signaling. Fourteen clinical studies (n = 3535 participants) assessed serum vitamin D level in women with ultrasound-proven fibroids, and all found an inverse correlation between serum vitamin D level and presence of fibroids. Five clinical studies (n = 472 patients) evaluated treatment of fibroids with vitamin D. Four of five studies showed vitamin D significantly inhibited fibroid growth. One pilot study (n = 109 patients) of vitamin D for secondary prevention of fibroids demonstrated smaller recurrent fibroids in the treated group. These studies provide evidence for vitamin D as a therapy for uterine fibroids and underscore the need for well-designed, randomized, placebo-controlled clinical trials.

FokI polymorphism of Vitamin D receptor gene and deficiency of serum Vitamin D increases the risk of breast cancer in North Indian women

INTRODUCTION

Breast cancer is a leading cause of cancer morbidity and mortality in females. Decreased availability of Vitamin D within breast cells, contributed by deficiency of serum Vitamin D and polymorphisms of Vitamin D receptor genes are possible risk factors for breast cancer.

OBJECTIVES

To study the association of FokI polymorphism of the Vitamin D Receptor gene with breast cancer in females and to study the levels of Vitamin D in breast cancer patients.

MATERIALS AND METHODS

VDR gene FokI genotyping was done by PCR-RFLP method and levels of serum Vitamin D were estimated by ELISA. Statistical analysis was done with SPSS v.21.

RESULTS

Serum Vitamin D was significantly lower in newly diagnosed breast cancer patients than in healthy controls (P = 0.016). Females with serum Vitamin D levels in the highest quartile have a lesser risk of breast cancer than those with serum Vitamin D levels in the lowest quartile (O. R = 2.4421, C.I = 1.09-5.45, P = 0.029). The risk of developing breast cancer is higher in women with the polymorphic T allele for VDR FokI genotype (CT/TT) than those homozygous for the wild C allele (CC). (O.R. = 4.295, C.I. = 2.2110-8.3451, p-value = <0.0001). Levels of serum Vitamin D were significantly higher (p < 0.001) in ER + patients and significantly low in those presenting with higher stages of cancer (p = 0.009).

CONCLUSIONS

FokI polymorphism of VDR gene and low circulating Vitamin D levels increase the risk of developing breast cancer in North Indian females. Serum Vitamin D can be used as a prognostic factor.

Association of vitamin D receptor gene polymorphisms with breast cancer risk

BACKGROUND

Recent literature suggests that vitamin D signaling has a protective effect against breast cancer risk. Thus, the aim of the present study was to find the association of vitamin D receptor (VDR) gene polymorphisms with breast cancer risk.

MATERIALS AND METHODS

Fok1, Bsm1, Apa1, and Taq1 polymorphisms were performed by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method, and Poly A polymorphism was carried out using PCR-SSCP in 140 breast cancer patients and 155 controls.

RESULTS

Odds ratio was significantly higher in both homozygous variant genotypes (LL) of Poly A polymorphism of VDR (odds ratio [OR] = 5.42, 95% confidence interval [CI] = 1.19-23.31, P = 0.02) and heterozygous variant genotypes (SL) of Poly A polymorphism of VDR (OR = 3.89, 95% CI = 1.10-13.7, P = 0.03). Fok1, Bsm1, Apa1, and Taq1 polymorphisms of VDR gene were not significantly associated with breast cancer risk.

CONCLUSION

Poly A polymorphism at the 3' untranslated region (UTR) of VDR gene was significantly associated with breast cancer risk in West Indian population.

Vitamin D, Th17 Lymphocytes, and Breast Cancer

Simple Summary

The effect of vitamin D₃ on the development of breast cancer (favorable, ineffective, or even unfavorable) depends on many factors, such as age, menopausal status, or obesity. The immunomodulatory effect of vitamin D may be unfavorable in case of breast cancer progression. The effect of vitamin D on Th17 cells may depend on disease type and patients’ age. Our goal was to summarize the data available and to find indications of vitamin D treatment failure or success. Therefore, in this review, we present data describing the effects of vitamin D₃ on Th17 cells, mainly in breast cancer.

Abstract

Vitamin D₃, which is well known to maintain calcium homeostasis, plays an important role in various cellular processes. It regulates the proliferation and differentiation of several normal cells, including immune and neoplastic cells, influences the cell cycle, and stimulates cell maturation and apoptosis through a mechanism dependent on the vitamin D receptor. The involvement of vitamin D₃ in breast cancer development has been observed in numerous clinical studies. However, not all studies support the protective effect of vitamin D₃ against the development of this condition. Furthermore, animal studies have revealed that calcitriol or its analogs may stimulate tumor growth or metastasis in some breast cancer models. It has been postulated that the effect of vitamin D₃ on T helper (Th) 17 lymphocytes is one of the mechanisms promoting metastasis in these murine models. Herein we present a literature review on the existing data according to the interplay between vitamin D, Th17 cell and breast cancer. We also discuss the effects of this vitamin on Th17 lymphocytes in various disease entities known to date, due to the scarcity of scientific data on Th17 lymphocytes and breast cancer. The presented data indicate that the effect of vitamin D₃ on breast cancer development depends on many factors, such as age, menopausal status, or obesity. According to that, more extensive clinical trials and studies are needed to assess the importance of vitamin D in breast cancer, especially when no correlations seem to be obvious.

Hormonal and genetic risk factors for breast cancer in a subset of the Karachi population

Objective

Appraisement of vitamin D receptor (VDR) polymorphisms is thought to be crucial to detect and make approaches targeting groups at risk for breast cancer (BC). Moreover, an understanding of genetic susceptibility can allow us to foresee several risk factors. The objective of our research is to evaluate the T to C base shift within TaqI (rs731236) in exon 9 and the A to G transition within Bsm1 (rs1544410) in intron 8 of the VDR gene as risk factors among BC patients.

Methods

The study involved 150 BC patients with a definite histological diagnosis. Controls were age-matched. DNA samples of Taq1 and Bsm1 were amplified according to the programmed protocol using a thermal cycler. The amplified PCR products were digested with Taq1 and Bsm1 restriction endonuclease enzymes. RFLP fragments were observed under UV light using 2% agarose gel and 0.5 ug/mL Ethidium bromide.

Results

The highest number of BC patients (32.7%) were in the 36 to 45 age group. Ethnicity and parity were found to be statistically significant. TaqI polymorphisms showed the highest genotypic frequency for TC (Tt) at 49 (32.7%), and there were 18 patients (12.0%) and controls with high statistical significance (OD 3.6, CI 2–6.4) and a p-value < 0.0001. However, for the Bsm1 genotype, the A (B) allele may be linked with protection from BC in individuals with the AA (BB) genotype.

Conclusion

A positive association was found between VDR genotypes and BC in a collective assay of Taq1 and BsmI. These results need further authentication in large cohort studies prior to applying these SNPs as promising BC markers in the Pakistani populace.

Vitamin D receptor gene polymorphisms and risk of breast cancer in Iranian women

OBJECTIVES

Vitamin D deficiency is a driving force of common cancers like breast cancer. Vitamin D receptor (VDR) can play a tumor suppressor role by helping the precise function of vitamin D in cells such as modulation TGF-β signaling pathway. This study aimed to investigate the association of VDR gene variants and susceptibility to breast cancer in Iranian women.

METHODS

Genomic DNAs were isolated from blood samples of 161 women with breast cancer and 150 healthy women. After amplification of five positions of VDR gene, the prepared amplicons were digested with TaqI, ApaI, BsmI, Cdx2, and FokI restriction enzymes.

RESULTS

Subsequently, the digested products were electrophoresed on the 1.5% agarose gel. Odds ratios (ORs) for breast cancer were calculated for genotypes and estimated haplotypes. Binary logistic regression analysis showed FokI (rs2228570), BsmI (rs1544410), and ApaI (rs7975232) polymorphisms had the significant distribution in patients than to the normal group. Analysis of linkage disequilibrium for all pairs of SNPs showed that D'-value between SNP TaqI and SNP BsmI was significantly (p ≤ 0.05). We observed that four major haplotypes of ApaI, BsmI, FokI, Cdx2, and TaqI SNPs significantly were in high frequency than predicted frequency. Among these four haplotypes, CGTAT haplotype was in a higher significant association than others with breast cancer risk (p-value = 0.0001).

CONCLUSION

Our results showed that FokI, BsmI, and ApaI of VDR polymorphisms associated with the risk of breast cancer in Iranian population.

Role of vitamin D3 in selected malignant neoplasms

Vitamin D₃ is a fat-soluble essential nutrient that affects multiple biologic functions in the organism through calcitriol and the vitamin D₃ receptor. This review article focuses on the results of studies on the relationship between the level of vitamin D₃ and cancer incidence or mortality, but also on the anticancer properties of vitamin D₃ that support its significant role in the prevention, clinical course, and overall survival rates of selected cancers (colorectal, prostate, breast, ovarian, endometrial, bladder, and malignant melanoma). The mechanisms of vitamin D₃ action involve, among others, polymorphism of vitamin D₃ receptor, cell cycle, caspases, and cancer stem cells. The level of vitamin D₃ has been also demonstrated to serve as a biomarker in some cancers, and high levels of vitamin D₃ can be conducive to successful cancer therapy.

Vitamin D intake, blood vitamin D levels, and the risk of breast cancer: a dose-response meta-analysis of observational studies

Epidemiological studies have indicated that blood vitamin D levels are linked to cancer. Here we conducted a dose-response meta-analysis based on published observational studies to evaluate the association of vitamin D intake and blood vitamin D levels with breast cancer susceptibility. PubMed, EMBASE, and Web of Science databases were searched up to January 2019. The pooled odds ratio (OR) and 95% confidence intervals (CIs) were extracted to estimate the risk. We identified 70 relevant studies on blood vitamin D levels (50 studies) and vitamin D intake (20 studies), respectively. Linear and nonlinear trend analyses were performed and showed that an increase in blood vitamin D levels by 5 nmol/l was associated with a 6% decrease in breast cancer risk (OR = 0.94, 95% CI = 0.93-0.96). Similar results were obtained for premenopausal (OR = 0.96, 95% CI = 0.93-0.99) and postmenopausal women (OR = 0.96, 95% CI = 0.94-0.98). The pooled OR of breast cancer risk for a 400IU/day increase in vitamin D intake was 0.97 (95% CI = 0.92-1.02). In conclusion, we found that breast cancer risk was inversely related to blood vitamin D levels; however, no significant association was observed in vitamin D intake.

Genetic and molecular biology of breast cancer among Iranian patients

Abstract

Background, Breast cancer (BC) is one of the leading causes of cancer related deaths in Iran. This high ratio of mortality had a rising trend during the recent years which is probably associated with late diagnosis.

Main body

Therefore it is critical to define a unique panel of genetic markers for the early detection among our population. In present review we summarized all of the reported significant genetic markers among Iranian BC patients for the first time, which are categorized based on their cellular functions.

Conclusions

This review paves the way of introducing a unique ethnic specific panel of diagnostic markers among Iranian BC patients. Indeed, this review can also clarify the genetic and molecular bases of BC progression among Iranians.

Vitamin D Status and Association of VDR Genetic Polymorphism to Risk of Breast Cancer in Ethiopia

Emerging evidence associates vitamin D deficiency and vitamin D receptor (VDR) genetic variations with risk for breast cancer. This study investigated the prevalence of vitamin D deficiency and its association with tumor characteristics and the implications of VDR genetic variations for risk of breast cancer in Ethiopia. This unmatched case–control study involved 392 female breast cancer patients and 193 controls. The plasma 25-hydroxyvitamin D (25(OH)D₃) level was quantified in chemotherapy-naïve (N = 112) and tamoxifen-treated patients (N = 89). Genotyping for the VDR common variant alleles rs7975232 (ApaI), rs2228570 (FokI), and rs731236 (TaqI) was done. Eighty-six percent of the patients were vitamin D deficient (<50 nmol/L). Chemotherapy-naïve breast cancer patients had a higher prevalence of vitamin D deficiency (91.9% vs. 78.3%) compared to the tamoxifen-treated group (p < 0.001). The prevalence of severe vitamin D deficiency (<25 nmol/L) was significantly higher in chemotherapy-naïve (41.1%) than tamoxifen-treated (11.2%) patients. Vitamin D deficiency was not significantly associated with tumor characteristics or VDR genotype. The rs2228570 GG genotype was associated with increased risk of breast cancer (OR = 1.44, 95% confidence interval = 1.01−2.06). Our result indicates that rs2228570 might be a moderate risk factor for breast cancer development in the Ethiopian population. The high prevalence of severe vitamin D deficiency in treatment-naïve breast cancer patients indicates the need for nutritional supplementation of vitamin D at the time of chemotherapy initiation.

Do genetic polymorphisms of the vitamin D receptor contribute to breast/ovarian cancer? A systematic review and network meta-analysis

BACKGROUND

To identify the most suitable genetic model for detecting the risk of breast cancer (BC)/ovarian cancer (OC) in specific populations.

METHODS

Databases were searched for related studies published up to October 2017. First, VDR genetic polymorphisms were compared in patients with and without cancer. Second, a network meta-analysis was used to reveal the relation between VDR genetic polymorphisms with disease outcomes. Subgroup analyses and a meta-regression were performed according to cancer types, ethnicity and genotypic method. The study is registered in PROSPERO with an ID: CRD42017075505.

RESULTS

Forty-five studies were eligible, which included 65,754 patients and 55 clinical analyses. Of genetic models, results suggested that the recessive model with the CDX2 polymorphism predicted the risk of BC in all cases. The recessive polymorphism model with the rs2228570 (FokI) polymorphism seemed to the best predictor of BC in Caucasian patients, whereas the homozygote model with the CDX2 polymorphism appeared to best predict BC in African-American patients. The homozygote model with the rs2228570 (FokI) polymorphism model appeared to detect the risk of OC in all cases, whereas the heterozygote model with the rs1544410 (BsmI) polymorphism seemed to detect the risk of OC in Caucasian patients.

CONCLUSIONS

By detecting the risk of BC, the recessive model with the rs2228570 (FokI) polymorphism is likely the best genetic model in Caucasian patients, and the homozygote model with the CDX2 polymorphism appears to be best genetic model in African-American patients. Moreover, for detecting clinical risk of OC, heterozygote models with the rs1544410 (BsmI) polymorphism is likely the best genetic model for detecting the risk of OC in Caucasian patients.

Association between vitamin D receptor gene polymorphisms and idiopathic hypocitraturia in a Chinese Bai population

Idiopathic hypocitraturia (IH) is a risk factor for urolithiasis. IH is associated with vitamin D receptor (VDR) gene single nucleotide polymorphisms (SNPs) in a Chinese Han population. However, this association between VDR SNPs and IH has not been recapitulated in a Chinese Bai population. The aim of this study is to investigate the association between VDR SNPs and IH in a Chinese Bai population. A total of 320 participants comprising of 200 Chinese Bai patients with IH and 120 Chinese Bai control participants with normal urinary citrate level were enrolled for this study. The VDR SNPs rs7975232, rs2228570, rs731236 and rs1544410 were detected by Sanger sequencing, and the association between these SNPs and the presence of IH in the Chinese Bai population was analyzed. The prevalence of VDR SNPs rs7975232 allele A and rs2228570 genotype TT was significantly higher in patients than in controls (p < 0.0125, after Bonferroni correction). The haplotype TCGC was a protective factor in the Chinese Bai population who otherwise might suffer from IH, while the haplotype TTGA was a risk factor. VDR SNPs rs731236 and rs1544410 have a linkage disequilibrium value of 0.811. VDR SNPs rs7975232, rs2228570, and haplotypes TCGC, TTGA are associated with IH in a Chinese Bai population.

Association between Vitamin D receptor (Cdx2, Fok1, Bsm1, Apa1, Bgl1, Taq1, and Poly (A)) gene polymorphism and breast cancer: A systematic review and meta-analysis

The purpose of this systemic review and meta-analysis was to examine the relationship between VDR gene polymorphisms and breast cancer. Literature was searched through PubMed database, Google scholar, and the web of knowledge from December 2015 to January 2017 and consists of 34 studies (26,372 cases and 32,883 controls). All statistical measures were done using STATA version 11.2. The heterogeneity among studies was tested using I² statistics. Mantel-Haenszel method and DerSimonian-Laird method were used to combine data from studies using both random-effect model and fixed-effect model, respectively. Potential publication bias was evaluated by Egger's test. Sensitivity analysis was also performed to evaluate the quality and consistency in results. The results of this meta-analysis revealed that VDR gene polymorphisms (Bsm1 bb vs BB; SOR = 1.18, 95% CI = 1.054-1.322, Apa1 aa vs AA; SOR = 1.18, 95% CI = 0.87-1.59, Poly (A) LL vs SS; SOR = 1.41, 95% CI = 1.06-1.88, Fok1 ff + Ff vs FF; SOR = 1.25, 95% CI = 0.896-1.759, Apa1 aa+Aa vs AA; SOR = 1.13, 95% CI = 0.95-1.35, Poly (A) LL + LS vs SS; SOR = 1.19, 95% CI = 1.00-1.43, Poly (A) L vs S; SOR = 1.18, 95% CI = 1.03-1.35) are associated with the breast cancer. Cdx2, Bgl1, and Taq1 do not show association with breast cancer. Thus, the finding of this meta-analysis concluded that VDR Bsm1, Apa1, Fok1, and Poly (A) gene polymorphisms may be susceptible for breast cancer development.

Association of the vitamin D receptor FokI gene polymorphism with sex- and non-sex-associated cancers: A meta-analysis

Currently higher morbidity and mortality rates are observed in cancer diseases, especially sex-dependent cancers. A positive role of endogenous vitamin D concentration in cancer diseases has been reported in many publications. Furthermore, there has been observed a relationship between serum vitamin D and testosterone concentrations in an elderly Caucasian population carrying the vitamin D receptor FokI gene polymorphism. The aim of this study was to investigate whether the vitamin D receptor FokI polymorphism is associated with cancerogenesis in sex-dependent cancers. The MEDLINE and ResearchGate databases were used to search for articles up to January 2017, and 96 articles concerning the FokI polymorphism were chosen. Odds ratios with 95% confidence intervals were used to assess the strength of associations between polymorphisms of vitamin D receptor and cancer risk in the described populations. The fixed-effects model and the DerSimonian-Laird random-effects model (with weights based on the inverse variance) were used to calculate summary odds ratios, and both within- and between-study variation were considered. Generally, the F variant reduces the risk of cancer by 4% (odds ratio = 0.96, p value = 0.0057). This effect is particularly evident in female sex-associated cancers (odds ratio = 0.96, 95% confidence interval: 0.93-0.99, p value = 0.0259), but it is not observed in non-sex-associated cancers. Polymorphism FokI is associated with breast and ovarian cancers.

Association of vitamin D receptor gene polymorphisms with breast cancer risk in an Egyptian population

This study aimed to explore whether genetic polymorphisms in vitamin D receptor are correlated to the breast cancer prevalence in an Egyptian population. Polymerase chain reaction-restriction fragment polymorphism was used to genotype three frequently analyzed vitamin D receptor gene single-nucleotide polymorphisms (rs1544410, rs7975232, and rs731236) and were identified by sequencing analysis. This is the first study that recorded a new single-nucleotide polymorphism in ApaI genotype within an Egyptian population and was registered with the accession number KY859868. The authors found that TC in rs731236, and TG in KY859868 single-nucleotide polymorphism showed significant distribution differences with an increased risk of breast cancer ( p < 0.05, odds ratio = 3.71, 95% confidence interval: 1.04-13.28 and p < 0.001, odds ratio = 7.05, 95% confidence interval: 2.02-24, respectively) compared with the wild-type TT genotype carriers in both single-nucleotide polymorphisms. In addition, the distribution frequencies of haplotypes ACT, GTT, and ATT in the patients group were significant, where ATT haplotype was associated with the highest breast cancer risk among all other haplotypes in the patients group ( p = 0.0023, odds ratio = 1.72, 95% confidence interval: 1.24-2.437). In conclusion, vitamin D receptors ApaI and TaqI confer high breast cancer susceptibility, particularly in Egyptians females carrying haplotype ATT. However, further studies focusing on the vitamin D receptor variants and haplotypes effects on vitamin D and vitamin D receptor concentrations, activities, and functionalities are needed.

Vitamin D Receptor Gene Polymorphism: Association with Susceptibility to Early-Onset Breast Cancer in Iranian, BRCA1/2-Mutation Carrier and non-carrier Patients

Mounting evidences support that vitamin D insufficiency or deficiency is a risk factor of breast cancer. Vitamin D receptor (VDR) is expressed in more than 36 cell types in different organs as in cancerous cells. Numerous allelic variants of VDR gene have been identified in human populations. Association of FokI (rs2228570) and BsmI (rs1544410) single nucleotide polymorphisms (SNPs) in VDR gene with the risk of breast cancer have been investigated in several studies, however, the published data are still inconsistent. Here, we investigated BsmI and FokI polymorphisms in Iranian young (≤ 35 years old) breast cancer patient with known BRCA1/2 germline mutations. VDR gene polymorphisms were detected by restriction fragment length polymorphism (RFLP) analysis in a cohort of 203 breast cancer patients and 214 controls from Iran. There was a significant association between the bb and Bb genotypes of the BsmI and the increased risk of breast cancer (OR 1.74, CI 1.06-2.87 and OR 2.08, CI 1.31-3.29, respectively). This association was maintained in the subgroup of BRCA1/2 mutation non carriers (OR 1.90, CI 1.15-3.20 and OR 1.75, CI 1.07-2.87 for bb and Bb genotypes respectively) and in the subgroup of BRCA1/2 mutation non-carriers with a family history of breast and/or ovarian cancer (OR 1.81, CI 1.08-3.05 and OR 1.65, CI 1.00-2.70 for bb and Bb genotypes respectively). None of the FokI homozygous or heterozygous genotypes were associated with the risk of breast cancer. In summary, the BsmI polymorphism of VDR gene may be associated with the risk of breast cancer in Iranian women.

Vitamin D Receptor Polymorphism and Breast Cancer Risk: A Meta-Analysis

The objective was to perform a meta-analysis to summarize the available evidence from prospective nested case-control studies on the association of vitamin D receptor (VDR) polymorphism and the risk of breast cancer.We searched PubMed, ISI web of science, EMBASE, and reference lists for included articles. Study specific odds ratios (ORs) and 95% confidence intervals (CIs) were pooled by using fixed-effect or random-effects models.Eight studies were included in the meta-analysis. There were no association between Fok1 gene allele contrast f versus F (OR: 0.859; 95%CI: 0.685-1.079), ff versus FF (OR: 0.893; 95%CI: 0.763-1.045), recessive models ff versus FF+Ff (OR: 0.932; 95%CI: 0.796-1.092), and dominant models ff+Ff versus FF (OR: 0.899; 95%CI: 0.780-1.037). The estimated VDR polymorphism showed no significant association between Bsm1, Taq1, Apa1 polymorphism, and breast cancer risk. In the Caucasian ethnic subgroup, no association was found between allele contrast, recessive models, and dominant models on Fok1, Bsm1 polymorphism, and breast cancer risk.VDR polymorphism (Fok1, Bsm1, Taq1, and Apa1) were not associated with the risk of breast cancer in the general population as well as Caucasian population.

Influence of Serum Levels of Vitamins A, D, and E as well as Vitamin D Receptor Polymorphisms on Micronucleus Frequencies and Other Biomarkers of Genotoxicity in Workers Exposed to Formaldehyde

BACKGROUND/AIM

Formaldehyde is classified as carcinogenic to humans, making it a major concern, particularly in occupational settings. Fat-soluble vitamins, such as vitamins A, D, and E, are documented as antigenotoxic and antimutagenic and also correlate with the cell antioxidant potential. This study investigates the influence of these vitamins on genotoxicity biomarkers of formaldehyde-exposed hospital workers.

METHODS

The target population were hospital workers exposed to formaldehyde (n = 55). Controls were nonexposed individuals (n = 80). The most used genotoxicity biomarkers were the cytokinesis-block micronucleus assay for lymphocytes and the micronucleus test for exfoliated buccal cells. Vitamins A and E were determined by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and vitamin D receptor (VDR) polymorphisms by real-time PCR.

RESULTS

Significant correlations were found between genotoxicity biomarkers and between vitamins A and E in controls. Multiple regression showed that vitamin A was significantly associated with a higher mean of nucleoplasmic bridges (p < 0.001), and vitamin E was significantly associated with a decreased frequency of nuclear buds (p = 0.045) in the exposed group. No effect of vitamin D was observed. The VDRBsmI TT genotype carriers presented higher means of all the genotoxicity biomarkers; however, we found no significant associations.

CONCLUSIONS

The study suggests that vitamin levels may modulate direct signs of genotoxicity.

Genetic variation in vitamin D-related genes and risk of breast cancer among women of European and East Asian descent

Studies of vitamin D-related genetic variants and breast cancer have been inconsistent. This study aimed to investigate associations of vitamin D-related polymorphisms and breast cancer risk among European and East Asian women and potential interactions with menopausal status and breast tumour subtypes. Data from a case-control study of breast cancer (1037 cases and 1050 controls) were used to assess relationships between 21 polymorphisms in two vitamin D-related genes (GC and VDR) and breast cancer risk. Odds ratios were calculated in stratified analyses of European and East Asian women, using logistic regression in an additive genetic model. An interaction term was used to explore modification by menopausal status. Polytomous regression was used to assess heterogeneity by breast tumour subtype. False discovery rate adjustments were conducted to account for multiple testing. No association was observed between GC or VDR polymorphisms and breast cancer risk. Modification of these relationships by menopausal status was observed for select polymorphisms in both Europeans (VDR rs4328262 and rs11168292) and East Asians (GC rs7041 and VDR rs11168287). Heterogeneity by tumour subtype was seen for three VDR polymorphisms (rs1544410, rs7967152 and rs2239186) among Europeans, in which associations with ER-/PR-/HER2+ tumours, but not with other subtypes, were observed. In conclusion, associations between vitamin D-related genetic variants and breast cancer were not observed overall, although the relationships between vitamin D pathway polymorphisms and breast cancer may be modified by menopausal status and breast tumour subtype.

Association between the BsmI Polymorphism in the Vitamin D Receptor Gene and Breast Cancer Risk: Results from a Pakistani Case-Control Study

BACKGROUND

Vitamin D is postulated to decrease the risk of breast cancer by inhibiting cell proliferation via the vitamin D receptor (VDR). Two common single nucleotide polymorphisms (SNPs) in the VDR gene, rs1544410 (BsmI) and rs2228570 (FokI), are inconsistently associated with breast cancer risk in Caucasian populations, while data for Asians are scarce. Here, we investigated the possible contribution of these SNPs to breast cancer risk in Pakistani breast cancer patients and in controls participating in a hospital-based breast cancer case-control study (PAK-BCCC).

METHODS

Genotyping of the BsmI and FokI SNPs was performed by PCR-based restriction fragment length polymorphism (RFLP) analysis of 463 genetically enriched female breast cancer cases with known BRCA1/2 status and in 1,012 controls from Pakistan. The association between SNP genotypes and breast cancer risk was investigated by logistic regression adjusted for potential breast cancer risk factors and stratified by BRCA1/2 status and family history. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported.

RESULTS

The b allele of the BsmI was associated with an increased breast cancer risk (per b allele OR 1.28, 95% CI 1.09-1.49, P = 0.003). Subgroup analysis revealed that this effect was restricted to BRCA1/2 non-carriers (per b allele OR 1.33, 95% CI 1.11-1.59, P = 0.002) and was stronger in those who reported a positive family history of breast and/or ovarian cancer (per b allele OR 1.64, 95% CI 1.20-2.22, P = 0.002). No association with breast cancer risk was detected for the FokI SNP.

CONCLUSIONS

The BsmI polymorphism in the VDR gene may be associated with an increased breast cancer risk in Pakistani women negative for BRCA1/2 germline mutations.

Vitamin D, Cancer Risk, and Mortality

Antiproliferative effects of 1,25-dihydroxyvitamin D, the biologically active form of vitamin D, are well established in various cell types by influencing cell differentiation and decreasing cell proliferation, growth, invasion, angiogenesis, and metastasis. Several meta-analyses showed that low serum levels of 25(OH)D was associated with colorectal cancer and overall mortality, while the association with cancer mortality was less consistent. VDR is a crucial mediator for the cellular effects of vitamin D and conflicting data have been reported for most malignancies. Beyond VDR, the biological effects of vitamin D are mediated by the vitamin D-binding protein. The GC (group-specific component) gene, encoding DBP, is highly polymorphic and several polymorphisms were investigated in association with cancer development with controversial results. Vitamin D supplementation was found to be associated with a reduced risk of overall mortality, reviewing all published trials on healthy subjects, whereas the evidence of an effect on cancer risk and mortality is less clear. Furthermore, long-term health effects of high doses of vitamin D, extended duration of supplementation, and the association with different baseline vitamin D levels remain to be investigated. In summary, epidemiological and preclinical studies support the development of vitamin D as preventative and therapeutic anticancer agents, with significant associations especially found for low vitamin D status with overall mortality and cancer outcome, more than cancer incidence. However, a definitive conclusion cannot be drawn and only large randomized clinical trials, both in healthy subjects and in cancer patients, will allow to draw definitive conclusions on the effect of vitamin D supplementation on cancer risk, prognosis, and mortality.

Vitamin D receptor gene polymorphisms and breast cancer risk among postmenopausal Egyptian women

Many studies reported that vitamin D can protect against various types of cancers. The mechanism of vitamin D action is mediated by the vitamin D receptor (VDR). VDR may have anti-stress function because it has been identified as p53 direct target gene. This research was designed to investigate the role of VDR polymorphisms BsmI (rs 1544410), ApaI (rs 7975232), TaqI (rs 731236), and FokI (rs 10735810) in pathogenesis of breast cancer using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The study included 130 postmenopausal breast cancer cases aged 49 to 65 years and 100 controls aged 50 to 72 years. A significantly increased risk of breast cancer among carriers of BsmI bb genotype was observed (OR = 2.5 (1.1-5.6), P = 0.025). Also, a significantly increased risk of breast cancer was detected among women carrying ApaI aa genotype (OR = 2.2 (1.02-4.5), P = 0.04), while no significant associations were observed between breast cancer risk and genotypes and allele frequencies of FokI and TaqI polymorphisms (P > 0.05). Our study showed that VDR gene polymorphisms (BsmI and ApaI) may contribute to breast cancer risk among postmenopausal women.

Vitamin D receptor Cdx-2 polymorphism and premenopausal breast cancer risk in southern Pakistani patients

Background

Vitamin D3 is a secoster oid that exerts its effect by binding to its nuclear receptor called vitamin D receptor (VDR), inducing apoptosis and thereby inhibiting cell proliferation in cancer cells. The VDR receptor, located in the nucleus, is known to regulate the functions of over 200 genes. Various allelic forms of hVDR have been discovered that increase susceptibility to various cancers. The VDR-Cdx2 polymorphism, located in the promoter region of exon 1e in the VDR gene, influences the functional activity of the receptor, since the hVDR lacks consensus TATA and CAAT boxes. The current investigation examines the association between VDR-Cdx2 polymorphism and breast cancer in premenopausal females from Southern Pakistan.

Methods

We conducted a case control study on 264 subjects (103 cases and 161 controls) who were recruited from a tertiary hospital located in Karachi, Pakistan. Genomic DNA was extracted from peripheral blood using a commercial kit method, and the VDR-Cdx2 polymorphism was genotyped using tetraprimer amplification refractory mutation system polymerase chain reaction (T-ARMS-PCR) method. Pearson chi square test was used to assess the association between VDR-Cdx2 genotype and breast cancer while genotype distribution in controls was evaluated by Hardy-Weinberg equilibrium (HWE). Breast cancer risk was calculated using odds ratios and 95% confidence intervals.

Results

The genotype distribution in the control group was in HWE (p > 0.05) for the VDR-Cdx2 polymorphism. A non-significant association was observed between VDR cdx2 polymorphism and breast cancer, however the GG genotype was at risk (OR = 1.832, 95% CI = 0.695–4.828) of developing breast cancer.

Conclusion

The GG genotype of Cdx2-VDR gene polymorphism may increase the risk of developing breast cancer in young female patients in South Pakistan. Further investigations examining additional single nucleotide polymorphisms (SNPs) in VDR are required to assess their relationships with breast cancer.

Vitamin D receptor gene polymorphisms and the risk for female reproductive cancers: A meta-analysis

Vitamin D receptor (VDR) gene polymorphisms and the risks for various breast and ovarian cancers have been reported in many epidemiological studies. However, the associations between VDR gene polymorphisms and the risk for each type of cancer are unclear. The aim of this meta-analysis was to evaluate the associations between VDR gene polymorphisms and female reproductive cancers. A systematic review was performed with the PubMed Science Direct, Scopus, and Google Scholar databases up to April 2014 using the search terms "vitamin D receptor or VDR" and "variant or polymorphism or SNP" with terms for breast, ovarian, cervical, endometrial, uterine, and vaginal cancers. A meta-analysis with the pooled odds ratios and 95% confidence intervals was carried out to assess the associations between VDR polymorphisms (Cdx-2, FokI, BsmI, ApaI, and TaqI) and the risks for reproductive cancers under the heterozygous, homozygous, dominant, and recessive models with fixed or random effects models. Six ovarian cancer studies (13 individual studies involving 4107 cases and 6661 controls) and 29 breast cancer studies (38 individual studies involving 16,453 cases and 22,044 controls) were included in our meta-analysis. Our results indicate that the FokI polymorphism was related to increased risks for breast and ovarian cancers, whereas the BsmI polymorphism was associated with a decreased risk for developing these cancers. Our comprehensive meta-analysis indicated that the FokI and BsmI VDR gene polymorphisms may be significantly associated with gynecological cancers. We suggest monitoring VDR gene polymorphisms as potential biomarkers in patients with gynecological malignancy.

Vitamin D receptor gene polymorphisms and haplotypes in Hungarian patients with idiopathic inflammatory myopathy

Idiopathic inflammatory myopathies are autoimmune diseases characterized by symmetrical proximal muscle weakness. Our aim was to identify a correlation between VDR polymorphisms or haplotypes and myositis. We studied VDR-BsmI, VDR-ApaI, VDR-TaqI, and VDR-FokI polymorphisms and haplotypes in 89 Hungarian poly-/dermatomyositis patients (69 females) and 93 controls (52 females). We did not obtain any significant differences for VDR-FokI, BsmI, ApaI, and TaqI genotypes and allele frequencies between patients with myositis and healthy individuals. There was no association of VDR polymorphisms with clinical manifestations and laboratory profiles in myositis patients. Men with myositis had a significantly different distribution of BB, Bb, and bb genotypes than female patients, control male individuals, and the entire control group. Distribution of TT, Tt, and tt genotypes was significantly different in males than in females in patient group. According to four-marker haplotype prevalence, frequencies of sixteen possible haplotypes showed significant differences between patient and control groups. The three most frequent haplotypes in patients were the fbAt, FBaT, and fbAT. Our findings may reveal that there is a significant association: Bb and Tt genotypes can be associated with myositis in the Hungarian population we studied. We underline the importance of our result in the estimated prevalence of four-marker haplotypes.

Associations among four polymorphisms (BsmI, FokI, TaqI and ApaI) of vitamin D receptor gene and end-stage renal disease: a meta-analysis

BACKGROUND AND AIMS

To evaluate the association between vitamin D receptor (VDR) BsmI, FokI, TaqI and ApaI gene polymorphisms and the risk of end-stage renal disease (ESRD).

METHODS

All eligible studies were included in our meta-analysis of a search of the PubMed, Cochrane and China National Knowledge Infrastructure (CNKI) databases according to predefined criteria. The fixed-effects or random-effects models were used to calculate the pooled odds ratio (OR) and corresponding 95% confidence interval (CI).

RESULTS

Thirteen studies including 1510 patients and 1812 controls were recruited for the analysis of the association between the VDR BsmI, FokI, TaqI and ApaI gene polymorphisms and the risk of ESRD.VDR BsmI B allele, BB genotype and bb genotype, FokI F allele, FF genotype and ff genotype, TaqI T allele, TT genotype and tt genotype, ApaI A allele, AA genotype and aa genotype were not associated with ESRD susceptibility for overall populations, Asians and Caucasians.

CONCLUSIONS

Results from the current study suggest that VDR BsmI, FokI, TaqI and ApaI gene polymorphisms are not associated with the risk of ESRD in the overall populations, Asians and Caucasians. However, more studies should be performed in the future.

Association between VDR polymorphisms and breast cancer: an updated and comparative meta-analysis of crude and adjusted odd ratios

There is a lot of debate on the relationship between vitamin D receptor polymorphisms and risk of breast cancer. Herein, we quantitatively analyzed the published case-control studies on this relationship by meta- analysis, performing a bibliographic search from Pubmed and CNKI up to July 31, 2013. The included case- control studies for Fok1, Bsm1, Taq1, Apa1, Cdx2 and Poly-A were 16, 19, 20, 10, 4, 6, respectively. Crude and adjusted odd ratios and 95% confidence intervals were calculated to present and compare the strength of any associations. The results of combined analyses indicated that Fok1, Bsm1, Apa1, Cdx2 and Poly-A were not significantly associated with the risk of breast cancer. In contrast, the tt genotype of Taq1 was a modest risk factor for breast cancer development (tt vs. TT: OR = 1.21, 95% CI: 1.01-1.44). To further confirm the above results, adjusted effects for the six polymorphisms were pooled based on adjusted ORs reported in the original studies. Adjusted ORs of Fok1, Apa1, Cdx2 and Poly-A were similar to the crude ORs. However, Bsm1 and Taq1 showed inconsistent results. For Bsm1, OR for BB vs. bb was 0.85, 95% CI: 0.74-0.98; for Taq1, OR for tt vs. TT was 1.03, 95% CI: 0.92-1.15, and not associated with risk. Subgroup analyses for crude ORs showed some association between Bsm1, Taq1 and breast cancer in Caucasians only, but for adjusted ORs, no associations were found. This meta-analysis suggests that the roles that Fok1, Apa1, Cdx2 and Poly-A polymorphisms play in breast cancer risk are negligible, with Bsm1 and Taq1 as possible exceptions. To be conservative, we still assumed that they may play a modest role in determining breast cancer risk. Further studies are needed to validate our findings.

Association between vitamin D receptor gene polymorphisms (Fok1 and Bsm1) and osteoporosis: a systematic review

Osteoporosis is a health concern characterized by reduced bone mineral density (BMD) and increased risk of fragility fractures. Many studies have investigated the association between genetic variants and osteoporosis. Polymorphism and allelic variations in the vitamin D receptor gene (VDR) have been found to be associated with bone mineral density. However, many studies have not been able to find this association. Literature review was conducted in several databases, including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for papers published between 2000 and 2013 describing the association between Fok1 and Bsm1 polymorphisms of the VDR gene and osteoporosis risk. The majority of the revealed papers were conducted on postmenopausal women. Also, more than 50% studies reported significant relation between Fok1, Bsm1 and osteoporosis. Larger and more rigorous analytical studies with consideration of gene-gene and gene-environment interactions are needed to further dissect the mechanisms by which VDR polymorphisms influence osteoporosis.

The role of the rs1544410 polymorphism of vitamin D receptor gene in breast cancer susceptibility

This study was devised to investigate the genetic effect modification of the BsmI polymorphism associated with the susceptibility to breast cancer. Case-control studies of the BsmI polymorphism and breast cancer were searched. A total of 17 eligible publications were included in our final analysis. Pooled ORs and 95 % CIs were obtained by means of fixed effects model. The general and stratified analyses according to ethnicity showed that the association between the BsmI polymorphism and the risk of breast cancer was not statistically significant. However, the subgroup of the hospital-based studies was found to confer protection against the disease (ORBBvs.bb = 0.83, 95 % CI = 0.71-0.97, P h = 0.571; OR BBvs.Bb+bb = 0.86, 95 % CI = 0.74-1.00, P h = 0.903; OR allele B vs. allele b = 0.92, 95 % CI = 0.86-0.99, P h = 0.337). Our results suggested that the presence of the BsmI polymorphism may contribute to the susceptibility of breast cancer. It is necessary that future large-scale studies should be conducted to further confirm the association between the BsmI polymorphism and breast cancer risk.

Vitamin D receptor polymorphism FokI and cancer risk: a comprehensive meta-analysis

Numerous studies investigated the associations of VDR polymorphisms with various types of cancer, suggesting an influence on cancer risk. FokI is one of the most frequently analysed polymorphisms but the results from single studies are contradictory. We performed a meta-analysis looking at the association between the FokI and all cancer sites and investigating sources of heterogeneity. We identified 77 independent studies up to April 2014. We presented the summary odds ratios (SORs) by cancer sites, ethnicity and study features. We found a significant association between FokI and ovarian cancer for ff genotype versus FF with no heterogeneity: SOR = 1.20 (95% CI: 1.02-1.41, I (2) = 0%). Moreover, we found a significant increased risk of any cancer: SOR = 1.08 (95% CI: 1.01-1.16, I (2) = 58%). A significant increased risk of any cancer is confirmed among Caucasian, among studies in Hardy-Weinberg equilibrium and nested case-control studies. Furthermore, among studies in Hardy-Weinberg equilibrium, skin cancer was found significantly associated with FokI: SOR = 1.24 (95% CI: 1.01-1.54; I (2) = 24%) for ff versus FF. The estimated number of cases attributable to ff genotype is 4221 for ovarian cancer and 52858 for skin cancer worldwide each year. No indication for publication bias was found for any cancer site. In conclusion, we found an overall significant association of FokI polymorphism with any cancer, with differential effect by ethnicity. In particular, the summary estimates indicate an increase risk for ovarian and skin cancer for ff versus FF. However, other factors may act modifying the association, and further studies are needed to clarify the impact on cancer risk.

BsmI polymorphism of vitamin D receptor gene and cancer risk: a comprehensive meta-analysis

The VDR gene is an important regulator of the vitamin D pathway, and the role of some of its polymorphisms on cancer risk was previously investigated. A trend of cancer risk reduction with the VDR BsmI B allele was observed for many cancer sites. We performed a comprehensive meta-analysis to investigate the role of VDR BsmI polymorphism on cancer risk, even according to different ethnicities. Summary odds ratios (SORs) were calculated with random-effects models and maximum likelihood estimation. We categorized studies into three groups ("moderate", "high" and "very high confidence") according to departure from Hardy-Weinberg equilibrium in controls, reported minor allele frequency and genotyping quality controls. The meta-analysis included 73 studies with 45,218 cases and 52,057 controls. We found a significant 6-7% reduction of cancer risk at any site respectively for carriers of Bb genotype (SOR; 95%CI: 0.94; 0.90-0.99) and for carriers of BsmI BB genotype (SOR; 95%CI: 0.93; 0.89-0.98) compared to bb carriers, and they remain statistically significant when we restricted the analysis to at least "high confidence" studies. For skin cancer, a significant risk reduction was observed for Bb carriers (SOR; 95%CI: 0.86; 0.76-0.98). We also found a significant reduction of colorectal cancer risk for BB and Bb+BB genotypes carriers, but these SORs were no more significant when we restricted the analysis to studies with "high confidence". When the analysis was stratified by ethnicity, we still observed a significant decreased risk for both Bb and BB compared to bb genotype among Caucasians: SORs (95%CI) for any cancer site were 0.97 (0.93-1.00) and 0.95 (0.91-0.99), respectively. Among other ethnic groups the inverse association was still present, but did not reach statistical significance. In conclusion, we suggest a weak effect of BsmI B allele in reducing cancer risk at any site, especially of the skin.

Vitamin D receptor is highly expressed in precancerous lesions and esophageal adenocarcinoma with significant sex difference

Bile acid reflux into the esophagus is important in the development of esophageal adenocarcinoma (EAC). Recently, vitamin D receptor (VDR) was recognized as a bile acid receptor as well as a vitamin receptor. Expression of VDR is reported to influence the development of various types of cancer, such as those of the breast, liver, and colon. However, little is known about the role of VDR in esophageal neoplasms. We investigated the clinicopathological role of VDR in esophageal tumors. We analyzed genomic DNA from 116 EACs for copy number aberrations. The VDR locus was amplified in 7% of EACs. Expression of the VDR protein was also detected by immunohistochemistry from tissue microarrays created from tissues of Barrett esophagus (BE), low-grade (LGD) and high-grade dysplasia (HGD), columnar cell metaplasia (CCM), squamous epithelium (SE), EAC, and esophageal squamous cell carcinoma (ESCC). The protein was highly expressed in 88% of CCM (58/66), 95% of BE (35/37), 100% of the 19 LGD, 94% of HGD (15/16), and 79% of EAC (86/109), but expression in SE and ESCC was rare. Female patients with EAC and CCM were significantly less likely to have high VDR expression than male patients. The overall survival rate was significantly different for patients with tumors exhibiting VDR amplification versus nonamplification. Our findings suggest that VDR plays a role in the early development of EAC through a bile acid ligand. The sex difference in VDR expression may help to explain why men have a high incidence of EAC.

Association between vitamin D receptor gene polymorphisms and breast cancer risk: a meta-analysis of 39 studies

Background

The associations between vitamin D receptor (VDR) gene polymorphisms and breast cancer risk were comprehensively investigated to clarify issues that remain controversial.

Methodology/Principal Findings

An electronic search was conducted of several databases, including PubMed, the Cochrane library, Web of Science, EMBASE, CBM and CNKI, for papers that describe the association between Fok1, poly-A repeat, Bsm1, Taq1 or Apa1 polymorphisms of the VDR gene and breast cancer risk. Summary odds ratios and 95% confidence intervals (CI) were estimated based on a fixed-effect model (FEM) or random-effect model (REM), depending on the absence or presence of significant heterogeneity. A total of 39 studies met the inclusion criteria. A meta-analysis of high-quality studies showed that the Fok1 polymorphism of the VDR gene was associated with an increased risk of breast cancer (ff vs. Ff+FF, OR: 1.09, 95%CI: 1.02 to 1.16, p = 0.007). No significant associations were observed between the other polymorphisms and breast cancer risk. No positive results were detected by pooling the results of all relevant studies.

Conclusion

A meta-analysis of high-quality studies demonstrated that the Fok1 polymorphism of the VDR gene was closely associated with breast cancer risk.

Systematic review and meta-analysis on vitamin D receptor polymorphisms and cancer risk

The vitamin D receptor (VDR) can influence cancer susceptibility through binding to vitamin D. However, the previous studies were contradictory. Therefore this meta-analysis was conducted to clarify the association between VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) and cancer risk. One hundred twenty-six studies were enrolled through PubMed. For VDR BsmI polymorphism, significantly increased cancer risks were observed in the overall analysis. In the further stratified analysis, increased risks were observed in colorectal and skin cancer, especially in Caucasian population. However, no significant associations were observed in other VDR polymorphisms in the overall analysis. In the further subgroup analysis, increased risks were found in oral, breast, and basal cell cancer while decreased risk was found in prostate cancer in t allele carriers of TaqI polymorphism. For VDR FokI polymorphism, increased risks were found in ovarian and skin cancer while decreased risk in glioma in f allele carriers. For VDR ApaI polymorphism, increased risk was observed in basal cell cancer, especially in Asian population in a allele carriers. In conclusion, these results indicated that b allele of BamI polymorphism was a risk factor for cancer susceptibility. Meanwhile, t allele of TaqI polymorphism was a risk factor for oral, breast, and basal cell cancer and a protective factor for prostate cancer. Moreover, f allele of FokI polymorphism was a risk factor for ovarian and skin cancer and a protective factor for glioma. Finally, a allele of ApaI polymorphism was a risk factor for basal cell cancer in Asian population.

Systematic review and meta-analysis on vitamin D receptor polymorphisms and cancer risk

The vitamin D receptor (VDR) can influence cancer susceptibility through binding to vitamin D. However, the previous studies were contradictory. Therefore this meta-analysis was conducted to clarify the association between VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) and cancer risk. One hundred twenty-six studies were enrolled through PubMed. For VDR BsmI polymorphism, significantly increased cancer risks were observed in the overall analysis. In the further stratified analysis, increased risks were observed in colorectal and skin cancer, especially in Caucasian population. However, no significant associations were observed in other VDR polymorphisms in the overall analysis. In the further subgroup analysis, increased risks were found in oral, breast, and basal cell cancer while decreased risk was found in prostate cancer in t allele carriers of TaqI polymorphism. For VDR FokI polymorphism, increased risks were found in ovarian and skin cancer while decreased risk in glioma in f allele carriers. For VDR ApaI polymorphism, increased risk was observed in basal cell cancer, especially in Asian population in a allele carriers. In conclusion, these results indicated that b allele of BamI polymorphism was a risk factor for cancer susceptibility. Meanwhile, t allele of TaqI polymorphism was a risk factor for oral, breast, and basal cell cancer and a protective factor for prostate cancer. Moreover, f allele of FokI polymorphism was a risk factor for ovarian and skin cancer and a protective factor for glioma. Finally, a allele of ApaI polymorphism was a risk factor for basal cell cancer in Asian population.

Current evidence on the four polymorphisms of VDR and breast cancer risk in Caucasian women

There have been a few epidemiological studies reporting VDR polymorphisms including Fok1, Bsm1, Apa1 and Taq1with breast cancer incidence and therefore risk. The results however are controversial, often due to smaller sample size. Concerning most of the studies were performed on Caucasian women, we conducted this comprehensive meta-analysis encompassing 38,151 cases and 47,546 controls (Fok1: 13,152 cases, 17,443 controls; Bsm1: 14,755 cases, 18,633 controls; Apa1: 3080 cases, 3412 controls; Taq1: 7164 cases, 8068 controls) to better understand roles of the polymorphisms in breast cancer development among Caucasian population. We did not find any association of the most controversial genotype Fok1 with breast cancer risk in Caucasian women (ff vs. FF: OR = 1.05, 95% CI = 0.95–1.22, P = 0.32 for heterogeneity; ff vs. Ff: OR = 1.05, 95% CI = 0.94–1.17, P = 0.40; ff vs. Ff + FF: OR = 1.07, 95% CI = 0.95–1.14, P = 0.37 and ff + Ff vs. FF: OR = 1.04, 95% CI = 0.99–1.09, P = 0.23). For Bsm1, Apa1 and Taq1, no significant association was also not found in the homozygote comparison, heterozygote comparison, recessive and dominant models respectively. In conclusion, the current analysis suggested that the four polymorphisms (Fok1, Bsm1, Apa1 and Taq1) of VDR may be not associated with breast cancer risk in Caucasian women.

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We added some new studies.

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The polymorphisms of VDR gene do not contribute to breast cancer susceptibility.

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This analysis is conducted in Caucasian women.

Lack of association between vitamin D receptor gene BsmI polymorphism and breast cancer risk: an updated meta-analysis involving 23,020 subjects

The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of vitamin D. A great number of studies regarding the association between BsmI polymorphism in the VDR gene and breast cancer have been published. However, the results have been contradicting. Therefore, we conducted a meta-analysis to re-examine the controversy. Published literatures from PubMed, Embase, and Chinese Biomedical Literature Database (CBM) were searched (updated to July 10, 2013). The principal outcome measure was the odds ratio (OR) with 95 % confidence interval (CI) for breast cancer risk associated with VDR BsmI polymorphism. With all studies involved, the meta-analysis results suggest no statistically significant association between VDR BsmI polymorphism and breast cancer risk (B vs. b, OR = 0.922, 95 % CI = 0.836–1.018, P = 0.108, I²  = 80.0 %; BB vs. bb, OR = 0.843, 95 % CI = 0.697–1.021, P = 1.75, I²  = 75.5 %; Bb vs. bb, OR = 0.930, 95 % CI = 0.814–1.063, P = 0.31, I²  = 73.1 %; BB+Bb vs. bb, OR = 0.906, 95 % CI = 0.787–1.043, P = 1.37, I²  = 78.7 %; BB vs. bb+Bb, OR = 0.899, 95 % CI = 0.786–1.028, P = 1.56, I²  = 61.0 %). The results were not changed when studies were stratified by ethnicity or source of controls. This meta-analysis suggested that there were no associations between VDR BsmI polymorphism and breast cancer.