Vitamin D receptor rs2228570 polymorphism and invasive ovarian carcinoma risk: pooled analysis in five studies within the Ovarian Cancer Association Consortium

Strong Cumulative Evidence of Associations of 6 Single Nucleotide Polymorphisms with Ovarian Cancer Risk: An Umbrella Review

Background: An increasing number of studies have reported associations between single nucleotide polymorphisms (SNPs) and ovarian cancer (OC) risk. However, some of the findings were inconsistent. The objective of this umbrella review was to evaluate the associations comprehensively and quantitatively. Methods: The protocol of this review was registered in PROSPERO (No. CRD42022332222). We searched the PubMed, Web of Science, and Embase databases to identify related systematic reviews and meta-analyses from inception to 15 October 2021. In addition to estimating the summary effect size by using fixed and random effects models and calculating the 95% prediction interval, we evaluated the cumulative evidence for associations with nominally statistical significance based on the Venice criteria and false positive report probability (FPRP). Results: Forty articles were included in this umbrella review, which referred to a total of 54 SNPs. The median number of original studies per meta-analysis was four, while the median number of total subjects was 3455. All included articles had greater than moderate methodological quality. A total of 18 SNPs were nominally statistically associated with OC risk; 6 SNPs (8 genetic models), 5 SNPs (7 genetic models), and 16 SNPs (25 genetic models) were identified as strong, moderate, and weak cumulative evidence, respectively. Conclusion: This umbrella review revealed associations between SNPs and OC risk and suggested strong cumulative evidence of associations of six SNPs (eight genetic models) with OC risk.

The association between single nucleotide polymorphisms and ovarian cancer risk: A systematic review and network meta-analysis

BACKGROUND

The relationship between single nucleotide polymorphisms (SNPs) and ovarian cancer (OC) risk remains controversial. This systematic review and network meta-analysis was aimed to determine the association between SNPs and OC risk.

METHODS

Several databases (PubMed, EMBASE, China National Knowledge Infrastructure, Wanfang databases, China Science and Technology Journal Database, and China Biology Medicine disc) were searched to summarize the association between SNPs and OC published throughout April 2021. Direct meta-analysis was used to identify SNPs that could predict the incidence of OC. Ranking probability resulting from network meta-analysis and the Thakkinstian's algorithm was used to select the most appropriate gene model. The false positive report probability (FPRP) and Venice criteria were further tested for credible relationships. Subgroup analysis was also carried out to explore whether there are racial differences.

RESULTS

A total of 63 genes and 92 SNPs were included in our study after careful consideration. Fok1 rs2228570 is likely a dominant risk factor for the development of OC compared to other selected genes. The dominant gene model of Fok1 rs2228570 (pooled OR = 1.158, 95% CI: 1.068-1.256) was determined to be the most suitable model with a FPRP <0.2 and moderate credibility.

CONCLUSIONS

Fok1 rs2228570 is closely linked to OC risk, and the dominant gene model is likely the most appropriate model for estimating OC susceptibility.

Lower vitamin D levels and VDR variants are risk factors for breast cancer: an updated meta-analysis

Inadequate vitamin D levels and vitamin D variants have been shown to be associated with breast cancer (BC), however the results are inconsistent. To reach a definitive conclusion the present meta-analysis was conducted. When compared to healthy controls, BC patients had reduced vitamin D levels (standard difference in means = -0.564, p = 0.003). The meta-analysis revealed that the FokI mutation was linked with an increased BC susceptibility (CC vs. TT: OR = 1.107, p = 0.001, CC vs. TC + TT: OR = 1.114, p = 0.020). There was no role of other VDR variants (BsmI, TaqI, and ApaI). FokI mutation and diminished vitamin D increase the likelihood of developing BC.

Association Between Vitamin D Binding Protein Gene Polymorphism (rs7041), Vitamin D Receptor, and 25-Hydroxyvitamin D Serum Levels With Prostate Cancer in Kurdish Population in West of Iran

Prostate cancer (PCa) pathology has been linked to vitamin D, vitamin D receptors (VDRs), and vitamin D binding proteins (VDBPs). We sought to investigate the association between VDR rs2228570 and rs1544410 as well as VDBP rs7041 polymorphisms and serum 25-hydroxyvitamin D (25(OH)-vitamin D) levels in PCa patients. Blood samples were collected from 111 PCa patients and 150 age-matched healthy volunteers. The VDR rs2228570 T/C, rs1544410 G/A, and VDBP rs7041 T/G genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). 25(OH)-vitamin D and PSA (Total and Free) serum levels were measured. The frequencies of VDBP genotypes T/G vs. T/T (56.5% vs. 44.5%, p = 0.01) according to the dominant model T/G + G/G vs. T/T (84.3% vs. 71.5%, p = 0.01) were significantly higher in PCa patients when compared to control group and considerably increased the risk of disease by 2.29, 1.44, and 2.13 folds respectively. Interestingly, the results demonstrated that PCa patients with the dominant model (T/G + G/G vs. T/T) of VDBP had significantly lower serum levels of vitamin D and higher serum levels of total and free PSA in comparison to the controls. Furthermore, when compared to controls, PCa patients with the dominant model T allele (T/G + G/G vs. TT) of VDBP had significantly higher vitamin D, total PSA, and free PSA concentrations. Serum levels of 25(OH)-vitamin D and rs7041 T/G polymorphism of the VDBP gene could be potential risk factors for PCa.

Association of vitamin D receptor gene polymorphisms with type 2 diabetes mellitus in Taif population: a case-control study

Abstract Several reasons may underlie the dramatic increase in type2 diabetes mellitus. One of these reasons is the genetic basis and variations. Vitamin D receptor polymorphisms are associated with different diseases such as rheumatoid arthritis and diabetes. The aim of this study is to investigate the possible association of two identified mutations ApaI (rs7975232) and TaqI (rs731236). Eighty-nine healthy individuals and Fifty-six Type 2 Diabetic (T2D) patients were investigated using RFLP technique for genotyping and haplotyping as well. The distribution of Apal genotypes was not statistically significant among the control (P=0.65) as well as for diabetic patients (P=0.58). For Taql allele frequencies of T allele was 0.61 where of G allele was 0.39. The frequency distribution of Taql genotypes was not statistically significant among the control (P=0.26) as well as diabetic patients (P=0.17). Relative risk of the allele T of Apa1 gene is 1.28 and the odds ratio of the same allele is 1.53, while both estimates were < 1.0 of the allele G. Similarly, with the Taq1 gene the relative risk and the odds ratio values for the allele T are 1.09 and 1.27 respectively and both estimates of the allele C were 0.86 for the relative risk and 0.79 for the odds ratio. The pairwise linkage disequilibrium between the two SNPs Taq1/apa1 was statistically significant in control group (D = 0.218, D' = 0.925 and P value < 0.001) and similar data in diabetic groups (D = 0.2, D' = 0.875 and P value < 0.001). These data suggest that the T allele of both genes Apa1 and Taq1 is associated with the increased risk of type 2 diabetes. We think that we need a larger number of volunteers to reach a more accurate conclusion.

Vitamin D receptor gene polymorphisms and uterine fibroid incidence in Caucasian women

INTRODUCTION

Uterine fibroids (UFs) are benign tumors which are derived from the smooth muscle cells of the uterus. Recent studies have demonstrated that the development of UFs can be particularly related to vitamin D and its receptor. Vitamin D comprises a group of fat-soluble steroid compounds which exert powerful, pleiotropic effects all over the human body. These actions are mediated by a specific type of receptor - vitamin D receptor (VDR). Recent findings have focused on the possible role of VDR genetic variations in the development of several types of diseases, e.g. autoimmune system diseases, various cancers and infections.

MATERIAL AND METHODS

The aim of the study was to evaluate the association between rs731236, rs1544410, and rs2228570 polymorphisms in the VDR (vitamin D receptor) gene and the incidence of UFs in Caucasian women. A total of 197 patients (114 fibroid-positive and 83 controls) were included in this retrospective cohort study. VDR gene polymorphisms rs731236 (TaqI), rs1544410 (BsmI) and rs2228570 (FokI) were determined using TaqMan and Simple Probes.

RESULTS

No statistically significant differences in the occurrence of selected VDR polymorphisms were observed between UF-positive women and healthy controls.

CONCLUSIONS

We found no association between rs731236, rs1544410, and rs2228570 VDR polymorphisms and UF incidence in Caucasian women. Larger sample size and multi-ethnic studies are necessary to investigate the matter further.

Ethnicity as modifier of risk for Vitamin D receptors polymorphisms: Comprehensive meta-analysis of all cancer sites

Vitamin D receptors polymorphisms are found to be associated with several cancers. Since their prevalence vary across ethnicities and ethnicity itself seems to influence the cancer risk, a comprehensive meta-analysis was performed to investigate the role of VDR Fok1, Bsm1, Taq1, Apa1, Cdx2 and cancer risk at specific organ sites. Odds ratios, calculated with random-effects models, summarized one-hundred-ninety-two independent studies for twenty-two cancer sites. Evidence was provided that Fok1, Bsm1, Cdx2, Apa1 and Taq1 are linked to cancer susceptibility for colorectal, lung, ovarian, skin, multiple myeloma and brain cancer. Stratifying by ethnicity, some differences were found, partially explained by minor allele frequency (MAF), for colorectal cancer, ovarian and prostate cancer in Caucasian and prostate cancer in Asian populations. In summary, ethnicity may be a modifier of cancer risk, in particular for hormone dependent cancers and it should be considered evaluating the effect of VDR on cancer risk.

Vitamin D Receptor Polymorphisms and Cancer

Increasing scientific evidence supports the link between vitamin D and cancer risk. The active metabolite 1,25(OH)2D exerts its activity by binding to the vitamin D receptor (VDR), an intracellular receptor that mediates transcriptional activation and repression of target genes. The binding of 1,25(OH)2D to VDR is able to regulate hundreds of different genes. VDR is active in virtually all tissues including the colon, breast, lung, ovary, bone, kidney, parathyroid gland, pancreatic b-cells, monocytes, T lymphocytes, melanocytes, keratinocytes, and also cancer cells.The relevance of VDR gene restriction fragment length polymorphisms for various types of cancer has been investigated by a great number of studies.We have carried out a systematic review of the literature to analyze the relevance of more VDR polymorphisms (Fok1, Bsm1, Taq1, Apa1, and Cdx2) for individual malignancies considering ethnicity as a key factor for heterogeneity.Up to December 2018, we identified 176 independent studies with data to assess the risk of breast, prostate, colorectal, skin (melanoma and non-melanoma skin cancer), lung, ovarian, kidney, bladder, gallbladder, esophageal, thyroid, head and neck, liver and pancreatic cancer, oral squamous cell carcinoma, non-Hodgkin lymphoma, multiple myeloma and sarcoma.Significant associations with VDR polymorphisms have been reported for prostate (Fok1, Bsm1, Taq1, Apa1, Cdx2), breast (Fok1, Bsm1, Taq1, Apa1, CdX2), colorectal (Fok1, Bsm1, Taq1, Apa1), and skin cancer (Fok1, Bsm1, Taq1). Very few studies reported risk estimates for the other cancer sites.Conflicting data have been reported for most malignancies, and at present, it is still not possible to make any definitive statements about the importance of the VDR genotype for cancer risk. It seems probable that other factors such as ethnicity, phenotype, 25(OH)D plasma levels, and UV radiation exposure play a role as confounding factors and introduce heterogeneity.To conclude, there is some indication that VDR polymorphisms may modulate the risk of some cancer sites and in future studies VDR genetic variation should be integrated also with assessment of vitamin D status and stratified by ethnicity.

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 receptor genetic polymorphisms and the risk of multiple sclerosis: A systematic review and meta-analysis

There are conflicting results regarding the exact effect of the vitamin D receptor (VDR) gene polymorphisms on the susceptibility to multiple sclerosis (MS). Therefore, we aimed to investigate the impact of four major studied VDR gene polymorphisms consisting of ApaI, BsmI, FokI, and TaqI on the risk of MS in the Iranian population. A literature search was performed in various databases to find case-control studies evaluating the association between VDR gene polymorphisms and MS risk in Iran. Data were extracted and odds ratios (OR) with 95% confidence intervals (CI) were calculated. Subgroup analyze was performed to detect potential sources of heterogeneity. A total of 1206 cases and 1402 controls in nine case-control studies were included. ApaI was the only variant which showed statistically significant relation in allelic (OR = 0.54 (95% CI: 0.37-0.79); P = 0.00), homozygote (OR = 3.48 (95% CI: 1.7-6.9); P = 0.00), dominant (OR = 0.56 (95% CI: 0.3-0.79); P = 0.01), and recessive (OR = 0.35 (95% CI: 0.18-0.66); P = 0.00) models. The TaqI polymorphism showed a significant negative association with MS only in the homozygote model (OR = 0.28 (95% CI: 0.08-0.9); P = 0.04). The BsmI polymorphism also showed significant relation in allelic (OR = 0.69 (95% CI: 0.51-0.94); P = 0.01), homozygote (OR = 0.46 (95% CI: 0.25-0.86); P = 0.01), and recessive OR = 0.56 (95% CI: 0.39-0.8); P = 0.00) models after performing sensitivity analysis. FokI polymorphism showed no significant association with MS risk. ApaI and TaqI TT genotype were found contributing to MS susceptibility and BsmI and FokI showed no relation with MS susceptibility in the Iranian population.

Vitamin D Exposure and Ovarian Cancer Risk and Prognosis

Given the poor prognosis of ovarian cancer and limited population-level strategies for early detection and long-term treatment success, knowledge of modifiable risk factors for prevention and improved prognosis is important. Vitamin D has received wide scientific interest in cancer research as having the potential to be one such factor. We carried out a systematic narrative review of the literature on vitamin D and ovarian cancer risk and survival. We included 17 case-control and cohort studies on ovarian cancer incidence. Five analyses were of sun exposure, among which three reported an inverse association. Of 11 analyses of dietary vitamin D, two reported an inverse association. Among five studies of 25(OH)D levels, an inverse association was reported in two. Across all studies the findings were inconsistent, but some recent studies have suggested that vitamin D exposure at earlier ages may be important. Only three studies examining vitamin D exposure in relation to survival among ovarian cancer survivors were identified and the findings were inconsistent. The evidence to date supports a null influence of vitamin D on both ovarian cancer risk and survival. Future research should ensure that exposure assessment captures vitamin D exposure from all sources and for the etiologically or prognostically pertinent period.

Vitamin D and Ovarian Cancer: Systematic Review of the Literature with a Focus on Molecular Mechanisms

Vitamin D is a lipid soluble vitamin involved primarily in calcium metabolism. Epidemiologic evidence indicates that lower circulating vitamin D levels are associated with a higher risk of ovarian cancer and that vitamin D supplementation is associated with decreased cancer mortality. A vast amount of research exists on the possible molecular mechanisms through which vitamin D affects cancer cell proliferation, cancer progression, angiogenesis, and inflammation. We conducted a systematic review of the literature on the effects of vitamin D on ovarian cancer cell.

Repurposing vitamin D for treatment of human malignancies via targeting tumor microenvironment

Tumor cells along with a small proportion of cancer stem cells exist in a stromal microenvironment consisting of vasculature, cancer-associated fibroblasts, immune cells and extracellular components. Recent epidemiological and clinical studies strongly support that vitamin D supplementation is associated with reduced cancer risk and favorable prognosis. Experimental results suggest that vitamin D not only suppresses cancer cells, but also regulates tumor microenvironment to facilitate tumor repression. In this review, we have outlined the current knowledge on epidemiological studies and clinical trials of vitamin D. Notably, we summarized and discussed the anticancer action of vitamin D in cancer cells, cancer stem cells and stroma cells in tumor microenvironment, providing a better understanding of the role of vitamin D in cancer. We presently re-propose vitamin D to be a novel and economical anticancer agent.

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

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

The role of vitamin D in ovarian cancer: epidemiology, molecular mechanism and prevention

Vitamin D is a fat-soluble prohormone best known for its role in maintaining calcium homeostasis. Large numbers of epidemiological studies have shown that vitamin D plays an important role in cancer prevention by regulating cellular proliferation and metabolism. Studies of the cellular mechanism of vitamin D in ovarian cancer strongly suggest that it exhibits protective and antitumorigenic activities through genomic and nongenomic signal transduction pathways. These results indicate that vitamin D deficiency results in an increase in the risk of developing ovarian cancer and that vitamin supplements may potentially be an efficient way of preventing cancer. Consequently, this review describes the epidemiology, molecular mechanism and evidence linking vitamin D deficiency to ovarian cancer.

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.

Pharmacogenomic survey of Qatari populations using whole-genome and exome sequences

The Arabs represent one of the most genetically heterogeneous populations characterized by a high prevalence of Mendelian disorders due to consanguinity. Population-scale genomic datasets provide a unique opportunity to understand the epidemiology of variants associated with differential therapeutic response. We analyzed publicly available genomic data for 1005 Qatari individuals encompassing five subpopulations. The frequencies of known and novel pharmacogenetic variants were compared with global populations. Impact of genetic substructure on the pharmacogenetic landscape of the population was studied. We report an average of three clinically actionable pharmacogenetic variants with FDA-recommended genetic testing per Qatari individual regardless of their genetic ancestry. We observed extensive differences in the frequencies of clinically actionable pharmacogenetic variants among the Qatari subpopulations. Our analysis revealed 3579 deleterious pharmacogenetic variants potentially altering the function of 1163 genes associated with 1565 drugs. This study has thus compiled the first comprehensive landscape of pharmacogenetic variants for any Arab population.

Genetic association between HER2 and ESR2 polymorphisms and ovarian cancer: a meta-analysis

Objective

The estrogen receptor (ER) and the human epidermal growth factor receptor 2 (HER2) each play an important role in female cancers. This study aimed to investigate the genetic association between three common single nucleotide polymorphisms (SNPs) and the risk of ovarian cancer. The SNPs investigated in this study were ESR2 rs1271572 and rs3020450 and HER2 rs1801200.

Methods

In this study, databases were electronically searched in a meta-analysis. Databases used were PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wanfang and Cochrane library. Case–control studies on the association between ESR2 and HER2 polymorphisms were selected according to inclusion and exclusion standard. Articles were evaluated for quality, and data were extracted.

Results

A total of 13 articles with 5,461 cases and 7,603 controls were included in this meta-analysis. The recessive model of ESR2 rs1271572 was shown to be significantly associated with the risk of ovarian cancer (p = 0.008, odds ratio [OR] [95% confidence interval {CI}] = 1.13 [1.03, 1.24]), and this significant association still existed in a subgroup analysis stratified by ethnicity (Asian: p = 0.04, OR [95% CI] = 1.92 [1.04, 3.56]; Caucasian: p = 0.02, OR [95% CI] = 1.12 [1.02, 1.23]). In addition, the distribution of the dominant model of ESR2 rs3020450 was significantly different in the total group (p = 0.02, OR [95% CI] = 0.71 [0.53, 0.95]) and the Caucasian subgroup (p = 0.02, OR [95% CI] = 0.67 [0.48, 0.94]). Furthermore, no significant association between allelic, dominant, codominant and recessive models of HER2 rs1801200 (V655I) and ovarian cancer was found (p > 0.05).

Conclusion

The recessive model of ESR2 rs1271572 and the dominant model of ESR2 rs3020450 might be susceptible factors for ovarian cancer.

Vitamin D receptor rs2228570 polymorphism is associated with LH levels in men exposed to anabolic androgenic steroids

OBJECTIVE

The primary aim of this study was to investigate the association between the vitamin D receptor polymorphisms rs2228570 (Fok1) and rs731236 (TaqI) and LH and FSH levels in relation to anabolic androgenic steroid (AAS) use.

RESULTS

Two cohorts were analyzed. Cohort 1 comprised healthy volunteers given single supra-physiological doses of 500 mg testosterone (n = 25). Cohort 2 comprised 45 self-reporting AAS users. Healthy volunteers homozygous for the C-allele of the Fok1 polymorphism exhibited 30% higher LH levels than T-carriers at baseline (p = 0.04) and twice the levels 14 days after testosterone administration (p = 0.01). AAS users homozygous for the C-allele had four times higher LH levels than TT-individuals (p < 0.05). FSH levels were not associated with Fok1 polymorphism, nor were LH and FSH levels associated with the TaqI polymorphism. In conclusion, there is an association between LH levels and the Fok1 VDR polymorphism and this difference is even more pronounced in AAS users and subjects with suppressed LH levels.

Vitamin D receptor rs2228570 polymorphism and susceptibility to ovarian cancer: An updated meta-analysis

AIM

The FokI polymorphism (C>T, rs2228570) of the vitamin D receptor gene is a coding nonsynonymous single nucleotide polymorphism in the translational initiation codon reported to have functional significance. Although the role of rs2228570 in the risk of ovarian cancer has been widely researched, the association is still unclear. We performed an updated meta-analysis to clarify this issue.

METHODS

Eligible studies were retrieved from electronic databases for the period 2007-2016. The association was measured by unadjusted odds ratio combined with 95% confidence intervals (CIs). Random-effect or fixed-effect models were used according to the heterogeneity of the studies. We further appreciated the strength of evidence according to Venice guidance.

RESULTS

Fourteen studies (4448 cases and 7242 controls) were included in the meta-analysis. Studies were predominantly conducted in Caucasian populations (4152 cases and 6693 controls). A dominant genetic model was determined to be the most appropriate genetic model. Overall meta-analysis showed a fixed-effect odds ratio of 1.14 (95% CI 1.05-1.23) under a dominant model. The fixed-effect odds ratios were 1.12 (95% CI 1.03-1.21) and 1.49 (95% CI 1.06-2.09) in Caucasian and Asian populations, respectively. The strength of the evidence was moderate.

CONCLUSION

The rs2228570 polymorphism increased the risk of ovarian cancer in Caucasian populations in a dominant genetic model. The role of this polymorphism in the risk of ovarian cancer in Asian populations should be further studied.

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.

Placental genetic variations in vitamin D metabolism and birthweight

INTRODUCTION

Vitamin D has pleiotropic functions that regulate fetal growth and development. We investigated associations of common placental genetic variations in vitamin D metabolism with birthweight.

METHODS

The study was conducted among participants (506 maternal-infant pairs) of a pregnancy cohort study. Data were collected using interviewer-administered questionnaires and post-delivery medical record abstraction. DNA, extracted from placental samples collected at delivery, was genotyped for eight single nucleotide polymorphisms (SNPs) in five vitamin D metabolism genes (CUBN, LRP2, VDR, GC, and CYP2R1). Linear and logistic regression models were used to evaluate associations of SNPs with birthweight and risk of low birthweight, respectively. Effect modification of associations by infant sex was examined using stratified analyses and interaction terms in regression models.

RESULTS

Mean (standard-deviation) birthweight among all, male, and female infants was 3482.1 (549.9), 3544.6 (579.0) and 3419.2 (512.5) grams, respectively. Each copy of the minor allele of rs2282679 (GC) was associated with a 68.6 g (95%CI:3.1134.7 g) increase in birthweight overall. Sex-specific associations were observed for SNP rs4667591 (LRP2) (p-value for interaction < 0.001). Each copy of the minor allele of rs4667591 was associated with a 124.7 g (95%CI:20.1229.0 g) increase in birthweight among female infants, and a suggested 81.6 g decrease in birthweight among male infants (95%CI:-183.7,20.5 g).

DISCUSSION

Our study identified overall and sex-specific associations between placental genetic variations in vitamin D metabolism and birthweight. If confirmed by larger replication studies, observed associations may provide insight into mechanistic underpinnings of the relationships between placental vitamin D metabolism and birth size.

Calcitriol Inhibits Cervical Cancer Cell Proliferation Through Downregulation of HCCR1 Expression

Calcitriol (1α,25-dihydroxyvitamin D3) has demonstrated anticancer activity against several tumors. However, the underlying mechanism for this activity is not yet fully understood. Our experiment was designed and performed to address one aspect of this issue in cervical cancer. HeLa S3 cells were cultured in media with various concentrations of calcitriol. Cell proliferation and cell cycle were assessed by spectrophotometry and flow cytometry, respectively. The mRNA and protein expression levels of human cervical cancer oncogene (HCCR-1) and p21 were determined by RT-PCR and Western blot, respectively. Results indicated that calcitriol inhibited HeLa S3 cell proliferation and induced cell cycle arrest at the G₁ phase. Calcitriol decreased HCCR-1 protein expression in a dose- and time-dependent manner. Furthermore, promoter activity analyses revealed that transcriptional regulation was involved in the inhibition of HCCR-1 expression. Overexpression of HCCR-1 in HeLa S3 cells reversed the inhibition of cell proliferation and G₁ phase arrest that resulted from calcitriol treatment. In addition, calcitriol increased p21 expression and promoter activity. HCCR-1 overexpression decreased p21 expression and promoter activity. Thus, our results suggested that calcitriol inhibited HeLa S3 cell proliferation by decreasing HCCR-1 expression and increasing p21 expression.

Polymorphic variants in the vitamin D pathway genes and the risk of ovarian cancer among non-carriers of BRCA1/BRCA2 mutations

Previous studies have produced inconsistent results regarding the contribution of single-nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene to ovarian cancer (OC) in various ethnicities. Additionally, little has been established with regard to the role of SNPs located in the retinoid X receptor α (RXRA), vitamin D-binding protein [also know as group-specific component (GC)] and VDR genes in non-carriers of the breast cancer 1/2 early onset (BRCA1/BRCA2) gene mutations. All participating individuals in the present study were evaluated for BRCA1 mutations (5382incC, C61G and 4153delA) with HybProbe assays, and for BRCA2 mutation (5946delT) using high-resolution melting (HRM) analysis. The associations of 8 SNPs located in RXRA, GC and VDR were investigated in OC patients without the BRCA1/BRCA2 mutations (n=245) and healthy controls (n=465). Genotyping of RXRA rs10881578 and rs10776909, and GC rs1155563 and rs2298849 SNPs was conducted by HRM analysis, while RXRA rs749759, GC rs7041, VDR BsmI rs1544410 and FokI rs2228570 genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. In addition, the gene-gene interactions among all tested SNPs were studied using the epistasis option in PLINK software. The lowest P-values of the trend test were identified for VDR rs1544410 and GC rs2298849 as P_trend=0.012 and P_trend=0.029, respectively. It was also found that, in the dominant inheritance model, VDR BsmI contributed to an increased risk of OC [odds ratio (OR), 1.570; 95% confidence interval (CI), 1.136-2.171; P=0.006; P_corr=0.048]. The gene-gene interaction analysis indicated a significant interaction between RXRA rs749759 and VDR FokI rs2228570 (OR for interaction, 1.687; χ²=8.278; asymptotic P-value=0.004; P_corr=0.032). In conclusion, this study demonstrated that certain VDR and RXRA SNPs may be risk factors for OC in non-carriers of BRCA1/BRCA2 mutations in the Polish population.

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 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.

Genome-wide association study identifies new susceptibility loci for epithelial ovarian cancer in Han Chinese women

Ovarian cancer is the leading cause of death from gynaecological malignancies worldwide. Here we perform a three-stage genome-wide association study (GWAS) in Han Chinese women to identify risk genetic variants for epithelial ovarian cancer (EOC). We scan 900,015 single-nucleotide polymorphisms (SNPs) in 1,057 EOC cases and 1,191 controls in stage I, and replicate 41 SNPs (P(meta)<10(-4)) in 960 EOC cases and 1,799 controls (stage II), and an additional 492 EOC cases and 1,004 controls (stage III). Finally, we identify two EOC susceptibility loci at 9q22.33 (rs1413299 in COL15A1, P(meta) = 1.88 × 10(-8)) and 10p11.21 (rs1192691 near ANKRD30A, P(meta) = 2.62 × 10(-8)), and two consistently replicated loci at 12q14.2 (rs11175194 in SRGAP1, P(meta) = 1.14 × 10(-7)) and 9q34.2 (rs633862 near ABO and SURF6, P(meta) = 8.57 × 10(-7)) (P<0.05 in all three stages). These results may advance our understanding of genetic susceptibility to EOC.

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.

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.

Vitamin D receptor FokI, BsmI, ApaI, and TaqI polymorphisms and susceptibility to ovarian cancer: a meta-analysis

OBJECTIVE

The goal of this study was to explore whether vitamin D receptor (VDR) polymorphisms are associated with susceptibility to ovarian cancer.

METHODS

Meta-analyses were conducted on the associations between the VDR FokI, BsmI, ApaI, and TaqI polymorphisms and ovarian cancer.

RESULTS

A total of 12 comparison studies were considered in the meta-analysis, which involved 3716 patients and 5059 controls. Meta-analysis of the VDR FokI polymorphism showed an association between ovarian cancer and the f allele in European populations (OR = 1.094, 95% CI = 1.028-1.163, p = 0.004). Meta-analysis revealed an association between ovarian cancer and the ApaI A allele in all study subjects and Europeans as a sub-group (OR = 1.235, 95% CI = 1.019-1.497, p = 0.032 and OR = 1.287, 95% CI = 1.029-1.609, p = 0.027, respectively). No association was found between ovarian cancer and the BsmI and Taq polymorphisms (OR for B allele = 1.084, 95% CI = 0.936-1.255, p = 0.280, OR for the T allele = OR = 0.847, 95% CI = 0.706-1.270, p = 0.716).

CONCLUSIONS

This meta-analysis suggests that the VDR FokI and ApaI polymorphisms are associated with susceptibility to ovarian cancer in European populations.

The VDR gene FokI polymorphism and ovarian cancer risk

The polymorphism of vitamin D receptor (VDR) gene is demonstrated to affect the activity of its encoding protein and the subsequent downstream effects mediated by vitamin D. Mutations in VDR gene FokI have been suggested in the development of various cancers. Whether the polymorphism of the VDR gene FokI confers risk to ovarian cancer still remains controversial across the published studies in different ethnicity. The aim of this meta-analysis was to determine the role of VDR gene FokI variant in the susceptibility to ovarian cancer. Six publications with 14 individual case-control studies involving a total of 10,964 subjects were finally included into our study after a comprehensive literature search of the PubMed, Embase, Web of Science, and Wanfang databases. The strength of the association between the VDR gene FokI polymorphism and ovarian cancer risk was estimated under the allelic (T vs. C), homozygous (TT vs. CC), additive (CT vs. CC), recessive (TT vs. CC + CT), and dominant (CT + TT vs. CC) gene models. The overall odds ratios (ORs) for the contrast models of T vs. C, TT vs. CC, CT vs. CC, and CT + TT vs. CC indicated that the VDR gene FokI variant was related to an increased risk of ovarian cancer (OR(T vs. C) = 1.09, 95 % confidence interval (CI) 1.03-1.15, P(OR) = 0.004; OR(TT vs. CC) = 1.17, 95 % CI 1.04-1.32, P(OR) = 0.011; OR(CT vs. CC) = 1.10, 95 % CI 1.01-1.20, P(OR) = 0.027; OR(CT + TT vs. CC) = 1.12, 95 % CI 1.03-1.21, P(OR) = 0.007). The stratified analysis among the Caucasians also identified a significant association between the VDR gene FokI polymorphism and the susceptibility to ovarian cancer. The present meta-analysis with large available published data has revealed that the VDR gene FokI polymorphism confers susceptibility to ovarian cancer, particularly among the Caucasian population.

Impact of vitamin D receptor VDR rs2228570 polymorphism in oldest old

BACKGROUND

Calcitriol, a key player in the regulation of mineral metabolism, influences, directly or by increasing plasma Ca2+ and phosphate levels, a multitude of physiological functions, such as bone mineralization, cell proliferation, immune response, carbohydrate metabolism, blood pressure, platelet reactivity, gastric acid secretion, cognitive function and mood. Calcitriol is mainly effective by stimulation of the Vitamin D receptor VDR. The responsiveness of VDR may be affected by gene variants, such as the FokI polymorphism (rs2228570). The GG gene variant is expected to be more active than the GA or AA gene variant. The present study explored the impact of VDR rs2228570 on survival and health of oldest old individuals (> 90 years).

METHODS

101 individuals > 90 years were examined and genotyped. As a result, the prevalence of GG, GA & AA was 36 (10 ♂, 26♀), 52 (24 ♂, 28♀) and 13 (4 ♂, 9♀), respectively, a prevalence not significantly different from the frequency in public available dbSNP and a population (n = 208) of young volunteers (average age 49 years).

RESULTS

As compared to carriers of GG, carriers of AA and/or GA displayed significantly (p<0.05) lower diastolic blood pressure (significant only in ♂), higher instrumental activity of daily life (IADL) score and more frequent hospital visits (significant only in ♂), significantly lower prevalence of depression (significant in ♀+♂), renal disease (significant only in ♀), allergy, peptic ulcer and urolithiasis (significant only in ♂), as well as significantly higher prevalence of transitoric ischemic attacks. In a younger population a German version of the NEO-FFI, allowing reliable and valid assessment of personality, revealed decreased neuroticism (significant only in ♂) and increased extraversion in AA carriers.

CONCLUSION

The Vitamin D receptor gene variant VDR rs2228570 has only little impact on life span but may affect a variety of pathophysiologically relevant functions including mood.

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

Objective

Vitamin D receptor (VDR) FokI polymorphism has been reported to influence ovarian cancer (OC) susceptibility, but the association between VDR BsmI polymorphism and OC risk remains controversial. To clarify the relationship between them, we performed a meta-analysis.

Methods

A comprehensive literature search was conducted to examine all the eligible studies of VDR BsmI polymorphism and OC risk. Odds ratios (OR) with 95% confidence intervals (95% CI) were used to assess the strength of this association.

Results

Seven separate comparisons consisting of 1977 OC cases and 2832 healthy controls were included in our meta-analysis. The pooled analyses showed no significant association between VDR BsmI G/A polymorphism and OC in all of the comparisons (AA vs GG: OR, 1.01; P = 0.919; AG vs GG: OR, 1.12; P = 0.087; AG + AA vs GG: OR, 1.10; P = 0.146; AA vs AG + GG: OR, 0.96; P = 0.629). However, subgroup analysis showed a significant contribution of the dominant inheritance model to OC development in the European group: AG + AA vs GG (OR, 1.43; P = 0.029); AG vs GG (OR, 1.46; P = 0.031).

Conclusions

Vitamin D receptor BsmI G/A gene variant might be a moderate risk factor of OC development in the European population instead of North America or Asian population.

Polymorphisms in the vitamin D Receptor (VDR) and the risk of ovarian cancer: a meta-analysis

The vitamin D receptor (VDR) principally mediates the anticancer activities of vitamin D. Various epidemiological studies have investigated the associations of VDR gene polymorphisms with ovarian cancer; however, the results have been inconclusive. In the current study, we evaluated, in a meta-analysis, the association of five common single nucleotide polymorphisms (SNPs) in the VDR gene (ApaI, BsmI, Cdx-2, FokI, and TaqI) with the risk of ovarian cancer. Six eligible studies, with a total of 4,107 cases and 6,661 controls, which evaluated the association of these variants and ovarian cancer risk, were identified from the MEDLINE and PubMed databases. The meta-analysis indicated that FokI was associated with an increased ovarian cancer risk, with a pooled odds ratio (OR) of 1.10 [95% confidence intervals (95% CI) = 1.00-1.20] for CT heterozygotes and 1.16 (95% CI = 1.02-1.30) for TT homozygotes relative to common CC carriers. Carriers of the T allele (also known as the f allele) showed an 11% (pooled OR = 1.11, 95% CI = 1.02-1.21; TT/CT vs. CC) increased risk of ovarian cancer relative to CC carriers. For FokI, no significant heterogeneity between the studies was found (I(2) = 0%, P = 0.62 for the Q test). There was no statistically significant association between the other four variants (ApaI, BsmI, Cdx-2 and TaqI) and risk of ovarian cancer. These data indicate that the polymorphism FokI on the VDR is a susceptibility factor for ovarian cancer. Nevertheless, more studies are warranted to elucidate the underlying mechanisms of the VDR in development of ovarian cancer.

Vitamin D and VDR gene polymorphism (FokI) in epithelial ovarian cancer in Indian population

Introduction

Vitamin D deficiency and vitamin D receptor (VDR) gene polymorphism, FokI, is reported to increase the risk of many cancers. Role of vitamin D and its receptor polymorphisms in ovarian cancer has not been clearly defined.

Objective

To study the levels of serum vitamin D and occurrence of vitamin D receptor gene polymorphism (FokI) in cases of ovarian cancer.

Material and methods

FokI genotyping was done by PCR-RFLP technique and vitamin D levels were estimated by chemiluminescence immunoassay.

Results

Serum vitamin D levels were significantly (p < 0.03) lower in ovarian cancer cases as compared to controls. The homozygous (TT) and heterozygous (CT) genotype predispose to the development of ovarian cancer in Indian population (OR: 2.37, 95% CI: 1.04-5.44) as compared to the homozygous (CC) genotype. Vitamin D deficiency and VDR gene polymorphism (FokI) act non-synergistically (p value < 0.4).

Conclusion

Low blood levels of vitamin D and VDR receptor polymorphism (FokI) might be a risk factor for the development of ovarian cancer. Other novel ligands of vitamin D receptor might be responsible for the non-synergistic effect.

rs12512631 on the group specific complement (vitamin D-binding protein GC) implicated in melanoma susceptibility

BACKGROUND

Solar radiation should be avoided in melanoma patients. Nevertheless, this is the main means by which the body produces vitamin D. Evidence suggests a protective role against cancer for vitamin D. Since vitamin D performs its function by binding the receptor encoded by the vitamin D-receptor gene (VDR), most studies have focused on polymorphisms (SNPs) within this gene. However, the gene encoding the vitamin D-binding protein (GC) appears in recent studies as a major player in the role of a serum vitamin D level regulator and in Cutaneous Melanoma (CM) predisposition.

METHODS

We performed a case-control study of 12 polymorphisms on GC and 9 on VDR among 530 cases and 314 controls from Spanish population.

RESULTS

We found association between SNP rs12512631, located 3'downstream of GC, and risk of CM that seems to fit a dominant model (OR 1.63 95%CI 1.23-2.17 p-value 7×10(-4)). This association remained Bonferroni's correction and after adjustment for potential confounders (p-value 3×10(-3)) and even after increasing the sample size to 1729 individuals (p-value 0.0129). Moreover, we confirmed evidence of an association between CM susceptibility and the linkage disequilibrium block marked by tag-SNP rs222016 (p-value 0.032). This block covers the GC intron 1 region, with probable regulatory functions.

CONCLUSION

To our knowledge, this is the first vitamin D pathway-related polymorphism study in melanoma risk conducted in the Spanish population. Furthermore, we show an association between polymorphisms in GC and melanoma risk, confirming recent studies in different populations.

Vitamin D receptor gene BsmI and FokI polymorphisms in relation to ovarian cancer risk in the Polish population

BACKGROUND

The role of vitamin D receptor (VDR) single-nucleotide polymorphisms (SNPs) in ovarian cancer has been studied in various populations; however, these results are discordant between different ethnicities.

METHOD

Using the polymerase chain reaction-restriction fragment length polymorphism method, we studied the prevalence of the VDR FokI (rs2228570) and BsmI (rs1544410) SNPs in women with ovarian cancer (n=168) and controls (n=182) in a Polish population.

RESULTS

We found a significant contribution of the BsmI SNP Bb+BB-versus-bb dominant inheritance model to ovarian cancer development (p=0.0221, p(corr)=0.0442, odds ratio [OR]=1.648 [95% confidence intervals, CI=1.073-2.532]). However, we did not observe an association of the BsmI SNP BB versus Bb+bb recessive inheritance model in patients (p=0.8059, OR=1.093 [95% CI=0.538-2.218]). Moreover, there was no association of FokI SNPs either in Ff+ff versus FF dominant or ff versus Ff+FF recessive inheritance models with ovarian cancer development (p=0.9924, OR=1.002 [95% CI=0.628-1.599] and p=0.1123, OR=1.542 [95% CI=0.901-2.638], respectively). The p-values of the trend test observed for the VDR BsmI and FokI SNPs in patients with ovarian cancer were p(trend)=0.0613 and p(trend)=0.3655, respectively.

CONCLUSION

Our study indicates that the VDR B gene variant might be a moderate risk factor of ovarian cancer development in the Polish population.

Investigation of the vitamin D receptor gene (VDR) and its interaction with protein tyrosine phosphatase, non-receptor type 2 gene (PTPN2) on risk of islet autoimmunity and type 1 diabetes: the Diabetes Autoimmunity Study in the Young (DAISY)

The present study investigated the association between variants in the vitamin D receptor gene (VDR) and protein tyrosine phosphatase, non-receptor type 2 gene (PTPN2), as well as an interaction between VDR and PTPN2 and the risk of islet autoimmunity (IA) and progression to type 1 diabetes (T1D). The Diabetes Autoimmunity Study in the Young (DAISY) has followed children at increased risk of T1D since 1993. Of the 1692 DAISY children genotyped for VDR rs1544410, VDR rs2228570, VDR rs11568820, PTPN2 rs1893217, and PTPN2 rs478582, 111 developed IA, defined as positivity for GAD, insulin or IA-2 autoantibodies on 2 or more consecutive visits, and 38 IA positive children progressed to T1D. Proportional hazards regression analyses were conducted. There was no association between IA development and any of the gene variants, nor was there evidence of a VDR*PTPN2 interaction. Progression to T1D in IA positive children was associated with the VDR rs2228570 GG genotype (HR: 0.49, 95% CI: 0.26-0.92) and there was an interaction between VDR rs1544410 and PTPN2 rs1893217 (p(interaction)=0.02). In children with the PTPN2 rs1893217 AA genotype, the VDR rs1544410 AA/AG genotype was associated with a decreased risk of T1D (HR: 0.24, 95% CI: 0.11-0.53, p=0.0004), while in children with the PTPN2 rs1893217 GG/GA genotype, the VDR rs1544410 AA/AG genotype was not associated with T1D (HR: 1.32, 95% CI: 0.43-4.06, p=0.62). These findings should be replicated in larger cohorts for confirmation. The interaction between VDR and PTPN2 polymorphisms in the risk of progression to T1D offers insight concerning the role of vitamin D in the etiology of T1D.

Vitamin D receptor (VDR) polymorphisms and risk of ovarian cancer in Caucasian and African American women

OBJECTIVE

Polymorphisms in the vitamin D receptor (VDR) gene have been shown in some studies to be associated with the risk of epithelial ovarian cancer (EOC) in Caucasian women. There are no published reports among African Americans.

METHODS

Case-control data from the North Carolina Ovarian Cancer Study were analyzed using logistic regression to determine the association between seven VDR polymorphisms and EOC in both Caucasians (513 cases, 532 controls) and African Americans (74 cases, 79 controls). In a larger sample of African-Americans (125 cases, 155 controls), we assessed associations between six SNPs in proximity of rs7975232.

RESULTS

African American women who carried at least one minor allele of rs7975232 were at higher risk for invasive EOC controlling for age and admixture with an odds ratio (OR) for association under the log-additive model of 2.08 (95% confidence interval (CI)=1.19, 3.63, p=0.010). No association was observed between any of the VDR variants and EOC among Caucasians. A larger sample of African Americans revealed a nearly two-fold increased risk of invasive EOC associated with rs7305032, a SNP in proximity to rs7975232 (R(2)=0.369) with a log-additive OR of 1.87 (95% CI=1.20, 2.93, p=0.006).

CONCLUSIONS

This is the first report showing VDR variants associated with ovarian cancer risk in African American women. A larger study of African American women is needed to confirm these findings. These results imply that vitamin D exposure is a possible modifiable risk factor of ovarian cancer among African Americans.

D-livering the message: the importance of vitamin D status in chronic liver disease

Vitamin D is synthesized predominantly in the liver and functions as an important secosteroid hormone with pleiotropic effects. While its key regulatory role in calcium and bone homeostasis is well established, recently there is increasing recognition that vitamin D also regulates cell proliferation and differentiation, and has immunomodulatory, anti-inflammatory and anti-fibrotic properties. These non-skeletal effects are relevant in the pathogenesis and treatment of many causes of chronic liver disease. Vitamin D deficiency is frequently present in chronic liver disease and may predict non-response to antiviral therapy in chronic hepatitis C. Small studies suggest that vitamin D supplementation improves sustained viral response rates, while 1α-hydroxylase polymorphisms and vitamin D-binding protein are also implicated in therapeutic outcomes. Vitamin D deficiency also closely relates to the severity of non-alcoholic fatty liver disease (NAFLD) and is implicated in the pathogenesis of insulin resistance, a key factor in the development of NAFLD. In preclinical studies, phototherapy and vitamin D supplementation ameliorate NAFLD histopathology, while vitamin D is a powerful anti-fibrotic against thioacetamide liver injury. In liver transplant recipients severe vitamin D deficiency predicts, and vitamin D supplementation prevents, acute cellular rejection. The role of vitamin D in the activation and regulation of both innate and adaptive immune systems may explain its importance in the above liver diseases. Further prospective studies are therefore warranted to investigate the therapeutic impact of vitamin D supplementation in chronic liver disease.

Dairy foods and nutrients in relation to risk of ovarian cancer and major histological subtypes

Inconsistent results for the role of dairy food intake in relation to ovarian cancer risk may reflect the potential adverse effects of lactose, which has been hypothesized to increase gonadotropin levels, and the beneficial antiproliferative effects of calcium and vitamin D. Using data from the New England case-control study (1,909 cases and 1,989 controls), we examined dairy foods and nutrients in relation to risk of ovarian cancer overall, histological subtypes and rapidly fatal versus less aggressive disease. We used logistic regression and polytomous logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). In models that were simultaneously adjusted for total (dietary plus supplements) calcium, total vitamin D and lactose, we observed a decreased overall risk of ovarian cancer with high intake of total calcium [Quartile 4 (Q4, >1,319 mg/day) vs. Quartile 1 (Q1, <655 mg/day), OR = 0.62, 95% CI = 0.49-0.79]; the inverse association was strongest for serous borderline and mucinous tumors. High intake of total vitamin D was not associated overall with ovarian cancer risk, but was inversely associated with risk of serous borderline (Q4, >559 IU/day vs. Q1, <164 IU/day, OR = 0.51, 95% CI = 0.34-0.76) and endometrioid tumors (Q4 vs. Q1, OR = 0.55, 95% CI = 0.39-0.80). We found no evidence that lactose intake influenced ovarian cancer risk or that risk varied by tumor aggressiveness in the analyses of intake of dairy foods and nutrients. The overall inverse association with high intake of calcium and the inverse associations of calcium and vitamin D with specific histological subtypes warrant further investigation.

Role of common genetic variants in ovarian cancer susceptibility and outcome: progress to date from the Ovarian Cancer Association Consortium (OCAC)

In this article, we review the current knowledge of the inherited genetics of epithelial ovarian cancer (EOC) susceptibility and clinical outcome. We focus on recent developments in identifying low-penetrance susceptibility genes and the role of the Ovarian Cancer Association Consortium (OCAC) in these discoveries. The OCAC was established to facilitate large-scale replication analyses for reported genetic associations for EOC. Since its inception, the OCAC has conducted both candidate gene and genome-wide association studies (GWAS); the latter has identified six established loci for EOC susceptibility, most of which showed stronger association with the serous histological subtype. Future GWAS and sequencing studies are likely to result in the discovery of additional susceptibility loci and may result in established associations with clinical outcome. Additional rare and uncommon ovarian cancer loci will likely be uncovered from high-throughput next-generation sequencing studies. Applying these novel findings to establish improved preventative and clinical intervention strategies will be one of the major challenges of future work.

Cataract and ovarian carcinoma: is the vitamin D hypothesis alive?

BACKGROUND

The major health benefit of exposure to solar UV radiation is the production of vitamin D, which is implicated in protection against several human cancers, including ovarian carcinoma. On the other hand, solar UV radiation is a recognized risk factor for cataract.

METHODS

This population-based case-control study of 709 women with primary invasive ovarian carcinoma and 1,101 controls examined the association of ovarian carcinoma risk with self-reported history of cataract as an indicator of high long-term exposure to UV radiation. ORs and 95% confidence intervals (CI) were estimated using multivariate logistic regression models.

RESULTS

Among controls, older age (P < 0.0001), history of type 2 diabetes (P = 0.04), and skin cancer (P = 0.03) were significant cataract risk predictors. A history of cataract, reported by 14% of cases and 17% of controls, was significantly associated with a reduced ovarian carcinoma risk (OR = 0.6; 95% CI, 0.4-0.8; P = 0.002). No heterogeneity was observed by tumor histology, stage, grade, study site, body mass index, or other ovarian cancer risk factors (P > 0.16).

CONCLUSION

These findings add indirect evidence to the hypothesis that lifetime vitamin D exposure may be inversely associated with risk of ovarian carcinoma.

IMPACT

The study suggests some potential new avenues for research. Additional studies are needed to further investigate the potential behavioral and biologic factors that might influence association of cataract with ovarian cancer.

Cod liver oil. A natural Vitamin D for preserving health

Vitamin D deficiency is pandemic in industrialized countries due to life-style changes. Recent studies suggest that besides bone-metabolism, vitamin D plays a central role in basic cell function like multiplication, differentiation and metabolism. This may explain that low vitamin D levels represent a risk factor for several apparently different diseases such as infective, autoimmune, neurodegenerative and cardiovascular diseases, as well as diabetes, osteoporosis and cancer. Accumulating evidences suggest that an adequate intake of vitamin D may significantly decrease prevalence and clinical outcome of these diseases. Estimated reduction of the economic burden might reach about 10 percent through normalizing vitamin D levels for these diseases. However, high doses of vitamin D monotherapy needs precaution for potential adverse effects and it should be substituted with the recommended doses of vitamin D in combination with synergistic vitamin A and omega 3 fatty acids, such as cod liver oil. Orv. Hetil., 2011, 152, 323–330.