Vitamin D-Related Genetic Variants, Interactions with Vitamin D Exposure, and Breast Cancer Risk among Caucasian Women in Ontario

Vitamin D regulates microbiome-dependent cancer immunity

A role for vitamin D in immune modulation and in cancer has been suggested. In this work, we report that mice with increased availability of vitamin D display greater immune-dependent resistance to transplantable cancers and augmented responses to checkpoint blockade immunotherapies. Similarly, in humans, vitamin D-induced genes correlate with improved responses to immune checkpoint inhibitor treatment as well as with immunity to cancer and increased overall survival. In mice, resistance is attributable to the activity of vitamin D on intestinal epithelial cells, which alters microbiome composition in favor of Bacteroides fragilis, which positively regulates cancer immunity. Our findings indicate a previously unappreciated connection between vitamin D, microbial commensal communities, and immune responses to cancer. Collectively, they highlight vitamin D levels as a potential determinant of cancer immunity and immunotherapy success.

The Impact of Vitamin D and Its Dietary Supplementation in Breast Cancer Prevention: An Integrative Review

Vitamin D deficiency is currently a significant public health issue closely linked to numerous diseases, such as breast cancer. This study aims to determine the estimated optimal serum levels of vitamin D to have a protective effect against breast cancer, in addition to exploring the biological mechanisms and risk factors involved. A literature search of articles published in the last 5 years was conducted, and simple statistical analyses using mean and standard deviation were performed to calculate the average concentration of vitamin D from different available studies. It has been observed that serum levels of vitamin D ≥ 40.26 ng/mL ± 14.19 ng/mL could exert a protective effect against breast cancer. Additionally, various biological mechanisms, such as those related to the immune system, and risk factors like diet implicated in this relationship were elucidated. Consequently, it can be concluded that proper serum levels of vitamin D may have a protective effect against breast cancer, and dietary supplementation may be an appropriate procedure to achieve these optimal vitamin D concentrations.

Genetic polymorphisms of CYP24A1 gene and cancer susceptibility: a meta-analysis including 40640 subjects

BACKGROUND

Whether cytochrome P450 24A1 (CYP24A1) polymorphism is associated with cancer susceptibility, the individual study results are still controversial. Therefore, we performed a comprehensive study to identify the association of CYP24A1 polymorphisms (rs4809960, rs6068816, rs2296241, rs4809957, rs2762939) with cancer susceptibility.

METHODS

Electronic databases including Cochrane Library, PubMed, and Embase were systematically retrieved for relevant publications. Fixed or random-effect model was selected to calculate odds ratios (ORs) with their 95% confidence intervals (95%CI).

RESULTS

Eighteen published articles were identified. The results indicated that rs4809960 polymorphism was associated with a decreased cancer risk in Caucasian (TT vs. TC+CC: P=0.035; C vs. T: P=0.016) and Asian population (CC vs. TC+TT: OR P=0.044; TT vs. TC+CC: P=0.021; CC vs. TT: P=0.020; C vs. T: P=0.008) and breast cancer risk (TT vs. TC+CC: P = 0.007; TC vs. TT: P=0.004; C vs. T: P=0.033). A significant association was found between rs2296241 polymorphism and esophageal squamous cell carcinoma risk (AA vs. GG+AG: P = 0.023) and prostate cancer susceptibility (A vs. G: P=0.022). Furthermore, rs4809957 polymorphism was associated with prostate cancer susceptibility in Caucasian (GG vs. GA+AA: P=0.029; GA vs. GG: P=0.022) and breast cancer susceptibility (AA vs. GG+GA: P=0.012; AA vs. GG, P=0.010; A vs. G: P=0.024). Additionally, rs6068816 polymorphism significantly decreased the lung cancer (CC vs. CT+TT: P = 0.016; TT vs. CC: P = 0.044; CT vs. CC: P = 0.036; T vs. C: P = 0.016) and breast cancer risk (TT vs. CC+CT: P = 0.043; TT vs. CC: P = 0.039). No association was found for rs2762939 polymorphism with overall cancer risk. However, for rs2296241, rs4809957, and rs6068816 polymorphisms, there were no significant differences after the Bonferroni correction.

CONCLUSION

The meta-analysis suggested that rs4809960 was associated with cancer risk and might be a genetic marker for predicting cancer risk. More large-scale and large-sample studies are necessary to further confirm these results.

Serum Vitamin D status and VDR (FokI) polymorphism association study in Pakistani females with breast cancer

Background

Breast cancer is most common in Pakistani women at young age compared to West where it is most common after 60 years of age. Variations in genes controlling vitamin D activity would play a role in determining the risk of breast cancer in women at early age.

Purpose

To determine the association of vitamin D receptors (VDR) gene polymorphisms (FokI) with breast cancer risk in Pakistani women.

Methods

FokI polymorphisms were studied through the polymerase chain reaction-restriction fragment length polymorphism technique on blood samples of 300 breast cancer and 300 healthy women.

Results

This study found that circulating level of 25(OH)D3 was significantly lower among breast cancer patients as well as healthy subjects. Patients with large tumor size had significantly lower vitamin D levels. VDR FokI genotypes were significantly distributed (P ≤ 0.00001) in Pakistani women with newly diagnosed breast cancer. A significant association between different FokI genotypes and circulating levels of 25(OH)D3 was found. Patients with FF genotype was significantly (P < 0.0001) associated with higher risk of breast cancer (OR 8.9, 95% CI 0.17-0.45) compared to Ff and ff genotype.

Conclusion

VDR gene FokI polymorphism was associated with plasma vitamin D level and significant differences found in mean serum vitamin D levels between genotype groups of FokI. The study concluded that FokI might be one of the contributors to increase relative risk of breast cancer in Pakistani women.

The risk model construction of the genes regulated by H3K36me3 and H3K79me2 in breast cancer

Abnormal histone modifications (HMs) can promote the occurrence of breast cancer. To elucidate the relationship between HMs and gene expression, we analyzed HM binding patterns and calculated their signal changes between breast tumor cells and normal cells. On this basis, the influences of HM signal changes on the expression changes of breast cancer-related genes were estimated by three different methods. The results showed that H3K79me2 and H3K36me3 may contribute more to gene expression changes. Subsequently, 2109 genes with differential H3K79me2 or H3K36me3 levels during cancerogenesis were identified by the Shannon entropy and submitted to perform functional enrichment analyses. Enrichment analyses displayed that these genes were involved in pathways in cancer, human papillomavirus infection, and viral carcinogenesis. Univariate Cox, LASSO, and multivariate Cox regression analyses were then adopted, and nine potential breast cancer-related driver genes were extracted from the genes with differential H3K79me2/H3K36me3 levels in the TCGA cohort. To facilitate the application, the expression levels of nine driver genes were transformed into a risk score model, and its robustness was tested via time-dependent receiver operating characteristic curves in the TCGA dataset and an independent GEO dataset. At last, the distribution levels of H3K79me2 and H3K36me3 in the nine driver genes were reanalyzed in the two cell lines and the regions with significant signal changes were located.

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.

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.

Evaluation of Vitamin D-Binding Protein Gene Polymorphism and its Plasma Concentration in Kurdish Patients With Breast Cancer in Sanandaj, Iran

Background: Several studies have indicated that polymorphism in vitamin D pathway genes is associated with breast cancer (BC) risk. Vitamin D-binding protein (VDBP) is a vital element in the metabolism of the vitamin D. VDBP carries the serum 25(OH) D3 to cells to promote vitamin D biological functions, such as cell proliferation and apoptosis. Missense SNP (rs.7041) is a common polymorphism in VDBP gene, which shows ethnic-specific allele frequencies. Objectives: This study presents the correlation of the rs7041 (Asp432Glu) gene polymorphism and plasma concentrations of VDBP in Kurdish patients with BC in Sanandaj, Iran. Methods: This cross-sectional study included 44 premenopausal BC patients and 44 healthy subjects. Plasma VDBP concentration was measured by enzyme-linked immunosorbent assay (ELISA). The VDBP (rs7041) was genotyped by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). Results: VDBP level was associated with a non-significant risk of BC (P=0.397). Frequencies of individuals with VDBP (rs7041) TT, TG, and GG genotypes were 13.6%, 52.2%, and 34.09% in case group and 11.3%, 79.5%, and 9.9% in control group, respectively. Genotype GG associated with increased susceptibility to developing BC (odds ratio [OR]=5.172, CI: 1.555-17.2, P=0.007). There was a significant reverse correlation between GT genotype and BC (OR=0.282, 95% CI: 0.110-0.722, P=0.008) Conclusion: The changes in the vitamin D pathway may increase susceptibility to develop BC in the Iranian Kurdish population.

CDX2-positive breast cancer presented with axillary lymph node metastases: A case report

BACKGROUND

The caudal type homeobox 2 transcription factor (CDX2) is a specific and sensitive marker for intestinal carcinoma, but usually not expressed in breast cancer. In CDX2-positive metastatic cancer of occult primary, the origin is highly suspicious of an enteric carcinoma.

CASE PRESENTATION

A 50-year-old woman complained of enlarged lymph nodes (LNs) in the right axilla. Mammography and ultrasonography scans showed no abnormal findings in her breasts. Core needle biopsy (CNB) revealed metastatic adenocarcinoma. Immunohistochemical staining was positive for CDX2 intensely. The primary tumor was suspicious of intestinal adenocarcinoma. A dynamic contrast-enhanced magnetic resonance imaging scan revealed an accentuated lesion which was detected using a second-look ultrasound, and diagnosed invasive ductal carcinoma by CNB. A partial mastectomy of the right breast with level I and II axillary LN dissection was performed. A few cells of primary cancer were expressed CDX2 and estrogen receptor. The final pathological diagnosis was T1bN3aM0 stage IIIC. The fluorescent double staining showed that CDX2 simultaneously expressed on the Ki67 positive cells of metastatic tumors. The adjuvant treatment included chemotherapy and radiation, followed by tamoxifen administration. The patient survived without any recurrences over the following 36 months.

CONCLUSIONS

We report a rare case of CDX2-positive metastatic breast cancer in the axillary LNs. As some literatures reported vitamin D pathways induced cancer cell apoptosis and inhibition, these metastatic cells of our case might play the effort of autoregulation of inhibiting progression.

A Bayesian Hierarchical Framework for Pathway Analysis in Genome-Wide Association Studies

BACKGROUND

Pathway analysis allows joint consideration of multiple SNPs belonging to multiple genes, which in turn belong to a biologically defined pathway. This type of analysis is usually more powerful than single-SNP analyses for detecting joint effects of variants in a pathway.

METHODS

We develop a Bayesian hierarchical model by fully modeling the 3-level hierarchy, namely, SNP-gene-pathway that is naturally inherent in the structure of the pathways, unlike the currently used ad hoc ways of combining such information. We model the effects at each level conditional on the effects of the levels preceding them within the generalized linear model framework. To deal with the high dimensionality, we regularize the regression coefficients through an appropriate choice of priors. The model is fit using a combination of iteratively weighted least squares and expectation-maximization algorithms to estimate the posterior modes and their standard errors. A normal approximation is used for inference.

RESULTS

We conduct simulations to study the proposed method and find that our method has higher power than some standard approaches in several settings for identifying pathways with multiple modest-sized variants. We illustrate the method by analyzing data from two genome-wide association studies on breast and renal cancers.

CONCLUSION

Our method can be helpful in detecting pathway association.

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.

Solar Ultraviolet Radiation and Breast Cancer Risk: A Systematic Review and Meta-Analysis

BACKGROUND

A protective relationship has been hypothesized between exposure to solar ultraviolet radiation (UVR) and the development of breast cancer.

OBJECTIVE

The objective of this study was to conduct a systematic literature review and meta-analysis of studies examining the association of exposure to solar UVR and breast cancer risk.

METHODS

We searched Medline, EMBASE, and Web of Science for all studies investigating exposure to solar UVR and breast cancer risk. Separate analyses were performed using estimates of time spent in the sun, and ambient UVR. Associations were estimated using DerSimonian and Laird random-effect models. Heterogeneity was investigated through subgroup analyses and I2 statistics.

RESULTS

Fourteen studies were included in the review and 13 in the meta-analysis, with the majority (n=8) conducted in North America. We observed a decreased risk of breast cancer for individuals spending ≥1h/d in the sun during summer months over a lifetime or usual adulthood compared with <1h/d [pooled relative risk (RR)=0.84; 95% CI: 0.77, 0.91]. Spending ≥2h/d in the sun had a similar protective effect as 1 to <2h/d when compared with <1h/d (RR=0.83; 95% CI: 0.75, 0.93 vs. 0.83; 95% CI: 0.78, 0.89). Exposure during adolescence was suggestive of a lower risk of breast cancer than exposure later in life (≥45 years of age) (RR=0.83; 95% CI: 0.71, 0.98 vs. 0.97; 95% CI: 0.85, 1.11). Ambient UVR was not associated with the risk of breast cancer (RR=1.00; 95% CI: 0.93, 1.09).

DISCUSSION

To our knowledge, this was the first meta-analysis to estimate the risk of developing breast cancer associated with time spent in the sun. The results suggest that obtaining greater than an hour a day in the sun during the summer months could decrease the risk of developing breast cancer. https://doi.org/10.1289/EHP4861.

Metabolic gene alterations impact the clinical aggressiveness and drug responses of 32 human cancers

Malignant cells reconfigure their metabolism to support oncogenic processes such as accelerated growth and proliferation. The mechanisms by which this occurs likely involve alterations to genes that encode metabolic enzymes. Here, using genomics data for 10,528 tumours of 32 different cancer types, we characterise the alterations of genes involved in various metabolic pathways. We find that mutations and copy number variations of metabolic genes are pervasive across all human cancers. Based on the frequencies of metabolic gene alterations, we further find that there are two distinct cancer supertypes that tend to be associated with different clinical outcomes. By utilising the known dose-response profiles of 825 cancer cell lines, we infer that cancers belonging to these supertypes are likely to respond differently to various anticancer drugs. Collectively our analyses define the foundational metabolic features of different cancer supertypes and subtypes upon which discriminatory strategies for treating particular tumours could be constructed.

Vitamin D pathway related polymorphisms and vitamin D receptor expression in breast cancer

Vitamin D deficiency is an emerging risk factor for breast cancer suggesting its role in breast cancer pathogenesis. Recent evidence suggests vitamin D receptor (VDR) expression is a prognosis predictor in breast cancer. We set out to determine the status of VDR expression in histologically characterized breast cancers, and whether common genetic variants modify VDR expression in breast cancer. One-hundred and twenty Kuwaiti female breast cancer fixed tissues were assessed for VDR expression to identify the level and location of its expression by immunohistochemistry. VDR variants (rs731236, rs2228570), and vitamin D binding protein (VDBP) variants (rs4588, rs7041) genotypes were ascertained in breast cancer specimens using Taqman genotyping assays. VDR nuclear expression correlated with low grade tumors (p = 0.01), whereas cytoplasmic expression correlated with lymph node positive tumors (p = 0.03). Absence of VDR expression was a marker for high-grade dedifferentiated tumors (p = 0.01). VDBP rs7041 associated with breast cancer risk (OR 1.92, 95% CI: 1.34 - 2.73; p = 0.0004), and VDR rs2228570 correlated with increased VDR cytoplasmic expression (p < 0.0001). In conclusion, VDR expression is altered in breast cancer confirming its involvement in breast cancer progression. Genetic factors appear to play a role in breast cancer risk, and may modify tumor sensitization to vitamin D.

Association of the vitamin D metabolism gene GC and CYP27B1 polymorphisms with cancer susceptibility: a meta-analysis and trial sequential analysis

Nowadays, vitamin D is known to have functions beyond bone formation, including inhibiting angiogenesis and promoting tumor apoptosis. CYP27B1 and group-specific component (GC), the main enzyme responsible for the degradation and transport of active vitamin D, play important role in many cancer-related cellular processes. Relationships between CYP27B1 and GC polymorphisms and cancer susceptibility have been widely investigated, whereas the results are inconsistent. We strictly searched EMBASE, PubMed, Web of Science, WanFang and CNKI electronic databases for relevant studies exploring the associations of GC (rs4588 and rs7041) and CYP27B1 (rs4646537, rs3782130) polymorphisms with cancer risks according to search strategy. Thirty-two studies published in 13 articles involving 15713 cases and 17304 controls were included. Our analyses suggested that rs4588 and rs7041 polymorphisms were significantly associated with overall cancer risk. Stratification analyses of ethnicity indicated that rs4588 polymorphism significantly increased cancer risk in Caucasians and Asians, while rs7041 polymorphism significantly increased cancer risk in Asians. When studies were stratified by cancer type, our results indicated that rs4588 significantly increased the risk of breast cancer and digestive system tumor, but not in prostate cancer and non-small cell lung cancer, while rs7041 significantly increased the risk of non-small cell lung cancer. Above associations were noteworthy findings as evaluated by false-positive report probabilities (FPRPs). There were no associations of rs4646537 and rs3782130 with overall cancer risks. Associations between CYP27B1 and GC polymorphisms and cancer risks were examined, and additional large samples are necessary to validate our results.

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.

Molecular Mechanism of Cancer Susceptibility Associated with Fok1 Single Nucleotide Polymorphism of VDR in Relation to Breast Cancer

Breast cancer is the leading cause of death among women worldwide. It is a multi-factorial disease caused by genetic and environmental factors. Vitamin D has been hypothesized to lower the risk of breast cancer via the nuclear vitamin D receptor (VDR). Genetic variants of these vitamin D metabolizing genes may alter the bioavailability of vitamin D, and hence modulate the risk of breast cancer.

Influence of Vitamin D in Advanced Non-Small Cell Lung Cancer Patients Treated with Nivolumab

Nivolumab is one of the most commonly used monoclonal antibodies for advanced non-small cell lung cancer treatment, to the extent that the presence of its anti-antibody is considered a negative prognostic factor. Vitamin D (VD) modulates expression of the genes involved in drug metabolism and elimination. Immune system regulation and immunodeficiency is frequent in non-small cell lung cancer patients. To date, no data have been reported about the relationship between nivolumab and VD. The aim of this study was to quantify plasma 25-hydroxyVD (25-VD) and 1,25-VD, nivolumab, and its anti-antibody before starting treatment (baseline) and at 15, 45 and 60 days of therapy. VD-pathway-associated gene single nucleotide polymorphisms (SNPs) were also evaluated. Molecules were quantified through enzyme-linked immunosorbent assay, and SNPs through real-time PCR. Forty-five patients were enrolled. Median nivolumab concentrations were 12.5 μg/mL, 22.3 μg/mL and 27.1 μg/mL at 15, 45 and 60 days respectively. No anti-nivolumab antibodies were found. Correlations were observed between nivolumab concentrations and 25-VD levels. Nivolumab concentrations were affected by VD-pathway-related gene SNPs. VDBP AC/CC genotype and baseline 25-VD < 10 ng/mL predicted a nivolumab concentration cut-off value of <18.7 μg/mL at 15 days, which was associated with tumor progression. This is the first study showing VD marker predictors of nivolumab concentrations in a real-life context of non-small cell lung cancer treatment.

The effect of vitamin D pathway genes and deferasirox pharmacogenetics on liver iron in thalassaemia major patients

Monitoring and treating iron overload is crucial in transfusion-dependent thalassaemia patients. Liver stiffness measurement by transient elastography and T2* magnetic resonance imaging represent non-invasive ways to evaluate the adequacy of the iron chelation treatment. We explored the role of single nucleotide polymorphisms involved in vitamin D metabolism, transport and activity, and in deferasirox metabolism on liver iron burden parameters. One-hundred and five beta-thalassaemia patients, treated with deferasirox, have been enrolled. Drug plasma C_trough and AUC were measured by a HPLC-UV method. Allelic discrimination was performed by real-time PCR. Age, UGT1A1-364 CT/TT and CYP27B1 -1260 GT/TT positively predicted liver stiffness values. Deferasirox dose and serum ferritin negatively predicted T2* data, whereas age and CYP2D6 1457 GG genotype positively influenced these values. The discoveries of this research may be useful for personalized medicine and the proposed method could be applied in patients with hereditary hemochromatosis and myelodysplastic syndromes.

Molecular evidence of role of vitamin D deficiency in various extraskeletal diseases

BACKGROUND

Role of vitamin D is not only limited to skeletal system but various other systems of the body, such as immune system, endocrine system, and cardiopulmonary system.

MATERIALS AND METHODS

It is supported by the confirmations of systems-wide expression of vitamin D receptor (VDR), endocrinal effect of calcitriol, and its role in immune responses.

RESULTS

Expression of VDR in various systems, immunoregulatory and hormonal response of vitamin D and deficiency of vitamin D may establish various pathologies in the body.

CONCLUSION

This review provides molecular evidence of relation of vitamin D with extra skeletal.

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.

Analyzing 74,248 Samples Confirms the Association Between CLU rs11136000 Polymorphism and Alzheimer's Disease in Caucasian But Not Chinese population

Clusterin (CLU) is considered one of the most important roles for pathogenesis of Alzheimer's Disease (AD). The early genome-wide association studies (GWAS) identified the CLU rs11136000 polymorphism is significantly associated with AD in Caucasian. However, the subsequent studies are unable to replicate these findings in different populations. Although two independent meta-analyses show evidence to support significant association in Asian and Caucasian populations by integrating the data from 18 and 25 related GWAS studies, respectively, many of the following 18 studies also reported the inconsistent results. Moreover, there are six missed and a misclassified GWAS studies in the two meta-analyses. Therefore, we suspected that the small-scale and incompletion or heterogeneity of the samples maybe lead to different results of these studies. In this study, large-scale samples from 50 related GWAS studies (28,464 AD cases and 45,784 controls) were selected afresh from seven authoritative sources to reevaluate the effect of rs11136000 polymorphism to AD risk. Similarly, we identified that the minor allele variant of rs11136000 significantly decrease AD risk in Caucasian ethnicity using the allele, dominant and recessive model. Different from the results of the previous studies, however, the results showed a negligible or no association in Asian and Chinese populations. Collectively, our analysis suggests that, for Asian and Chinese populations, the variant of rs11136000 may be irrelevant to AD risk. We believe that these findings can help to improve the understanding of the AD's pathogenesis.

Effect of pharmacogenetic markers of vitamin D pathway on deferasirox pharmacokinetics in children

OBJECTIVES

Patients with β-thalassemia major have extremely low vitamin D levels, owing to reduced intestinal absorption, subicteric tint, and/or iron-induced higher pigmentation. We investigated whether some polymorphisms within the VDR, CYP24A1, CYP27B1, and GC genes could play a role in deferasirox pharmacokinetics in a cohort of pediatric patients.

PATIENTS AND METHODS

Eighteen children with β-thalassemia were enrolled. Drug plasma concentrations at the end of dosing interval (Ctrough) and after 0, 2, 4, 6, and 24 h of drug administration were measured by a HPLC-UV method. Allelic discrimination for VDR (TaqI, FokI, BsmI, Cdx2, and ApaI), CYP24A1 (22776, 3999 and 8620), CYP27B1 (2838 and -1260), and GC (1296) single nucleotide polymorphisms was performed by real-time PCR.

RESULTS

CYP24A1 8620 AG/GG group negatively predicted Ctrough in regression analysis (P=0.012). ApaI AA genotype resulted as a negative predictor of Ctrough (P=0.025) and area under the concentration curve (P=0.007); FoKI CC genotype remained as area under the concentration curve positive predictor (P=0.008) and TC/CC group as half-life (t1/2) (P=0.003) and volume of distribution (Vd) (P=0.011) negative one; TaqI TC/CC was retained as a negative predictor of drug maximum concentration (Cmax) (P=0.004). Moreover, GC 1296 TG/GG seemed able to predict lower time to reach drug maximum concentration (Tmax) (P=0.033).

CONCLUSION

Our preliminary experience suggested the potential usefulness of vitamin D pharmacogenetic to better understand deferasirox interindividual variability, also in pediatric patients.

Vitamin D exposure and Risk of Breast Cancer: a meta-analysis

The relationship between vitamin D and breast cancer is still controversial. The present meta-analysis examines the effects of the 25(OH)D, 1,25(OH)2D and vitamin D intake on breast cancer risk. For this purpose, a PubMed, Scopus and Web of Science-databases search was conducted including all papers published with the keywords “breast cancer” and “vitamin D” with at least one reported relative risk (RR) or odds ratio (OR). In total sixty eight studies published between 1998 and 2018 were analyzed. Information about type of study, hormonal receptors and menopausal status was retrieved. Pooled OR or RR were estimated by weighting individual OR/RR by the inverse of their variance Our study showed a protective effect between 25 (OH) D and breast cancer in both cohort studies (RR = 0.85, 95%CI:0.74–0.98) and case-control studies (OR = 0.65, 95%CI: 0.56–0.76). However, analyzing by menopausal status, the protective vitamin D – breast cancer association persisted only in the premenopausal group (OR = 0.67, 95%CI: 0.49–0.92) when restricting the analysis to nested case-control studies. No significant association was found for vitamin D intake or 1,25(OH)2D. Conclusion: This systematic review suggests a protective relationship between circulating vitamin D (measured as 25(OH) D) and breast cancer development in premenopausal women.

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.

SNPs related to vitamin D and breast cancer risk: a case-control study

BACKGROUND

It has been suggested that vitamin D might protect from breast cancer, although studies on levels of vitamin D in association with breast cancer have been inconsistent. Genome-wide association studies (GWASs) have identified several single-nucleotide polymorphisms (SNPs) to be associated with vitamin D. The aim of this study was to investigate such vitamin D-SNP associations in relation to subsequent breast cancer risk. A first step included verification of these SNPs as determinants of vitamin D levels.

METHODS

The Malmö Diet and Cancer Study included 17,035 women in a prospective cohort. Genotyping was performed and was successful in 4058 nonrelated women from this cohort in which 865 were diagnosed with breast cancer. Levels of vitamin D (25-hydroxyvitamin D) were available for 700 of the breast cancer cases and 643 of unaffected control subjects. SNPs previously associated with vitamin D in GWASs were identified. Logistic regression analyses yielding ORs with 95% CIs were performed to investigate selected SNPs in relation to low levels of vitamin D (below median) as well as to the risk of breast cancer.

RESULTS

The majority of SNPs previously associated with levels of vitamin D showed a statistically significant association with circulating vitamin D levels. Heterozygotes of one SNP (rs12239582) were found to have a statistically significant association with a low risk of breast cancer (OR 0.82, 95% CI 0.68-0.99), and minor homozygotes of the same SNP were found to have a tendency towards a low risk of being in the group with low vitamin D levels (OR 0.72, 95% CI 0.52-1.00). Results from stratified analyses showed diverse associations with breast cancer risk for a few of the tested SNPs, depending on whether vitamin D level was high or low.

CONCLUSIONS

SNPs associated with vitamin D may also be associated with the risk of breast cancer. Even if such a risk is small, the allele frequency of the SNP variants is high, and therefore the population attributable risk could be substantial. It is also possible that vitamin D levels may interact with genomic traits with regard to breast cancer risk.

Role of CYP24A1, VDR and GC gene polymorphisms on deferasirox pharmacokinetics and clinical outcomes

β-Thalassemia patients develop deficiency in vitamin D absorption and liver hydroxylation, resulting in extremely low calcitriol levels. We explored the role of single-nucleotide polymorphisms (SNPs) involved in vitamin D metabolism, transport and activity on deferasirox pharmacokinetics and outcomes (effectiveness trough levels (C_trough) and the area under the curve (AUC) cutoffs of 20 μg ml^-1 and 360 μg ml^-1 h^-1, respectively; nonresponse AUC limit of 250 μg ml^-1 h^-1). Ninety-nine β-thalassemic patients were enrolled. Drug plasma C_trough and AUC were measured by the high-performance liquid chromatography system coupled with an ultraviolet determination method. Allelic discrimination for VDR, CYP24A1, CYP27B1 and GC gene SNPs was performed by real-time PCR. CYP24A1 22776 TT significantly influenced C_min and negatively predicted it in regression analysis. CYP24A1 3999 CC was associated with C_trough and C_min and was a negative predictor of T_max, whereas CYP24A1 8620 GG seemed to have a role in C_trough, AUC, t_1/2 and C_min, and was an AUC negative predictor factor. Considering treatment outcome, Cdx2 and GC 1296 were retained in regression analysis as AUC efficacy cutoff negative predictors.

The associations between CYP24A1 polymorphisms and cancer susceptibility: A meta-analysis and trial sequential analysis

PURPOSE

Published data have shown that vitamin D may have a protective effect on cancer development. CYP24A1, the main enzyme responsible for the degradation of active vitamin D, plays an important role in many cancer related cellular processes. Up to now, relationships between CYP24A1 polymorphisms and cancer susceptibility have been widely investigated, whereas the results are inconsistent. The aim of present meta-analysis was to explore the associations between CYP24A1 polymorphisms and cancer susceptibility.

METHODS

We searched on EMBASE, Web of Science, PubMed and China National Knowledge Infrastructure (CNKI) electronic databases (up to July 1, 2017) for relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to make the evaluation clear.

RESULTS

Twenty-nine studies published in eight publications involving 20,593 cases and 25,458 controls were included. Five CYP24A1 gene polymorphisms were evaluated: rs2181874, rs2585428, rs4809960, rs6022999, and rs6068816. Our analyses suggested that rs2585428 and rs4809960 polymorphisms were significantly associated with overall cancer risk. Stratification analyses of ethnicity indicated that rs2585428 and rs4809960 polymorphisms decreased the risk of cancer among Caucasians. When studies were stratified by cancer type, our results indicated that rs2585428 significantly decreased the risk of pancreas cancer, while rs4809960 significantly decreased the risk of breast cancer. There were no associations of rs2181874, rs6022999, or rs6068816 with overall cancer risks.

CONCLUSION

Associations between CYP24A1 polymorphisms and cancer risks were examined, and additional multi-center studies with large samples are necessary to validate our results.

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.

Single-Nucleotide Polymorphisms in Vitamin D-Related Genes May Modify Vitamin D-Breast Cancer Associations

Background: We previously observed that high serum 25-hydroxyvitamin D (25(OH)D; >38.0 ng/mL) was inversely associated with breast cancer. Here, we examined effect modification by SNPs in vitamin D-related genes.Methods: The Sister Study enrolled 50,884 U.S. women who had a sister with breast cancer, but who had never had breast cancer themselves. Using a case-cohort design, we compared 1,524 women who developed breast cancer within 5 years to 1,810 randomly selected participants. We estimated ratios of HRs (RHRs) for the 25(OH)D-breast cancer association per copy of the minor allele using Cox proportional hazards models. We considered 82 SNPs in 7 vitamin D-related genes (CYP24A1, CYP27B1, CYP2R1, GC, DHCR7/NADSYN1, RXRA, and VDR). We also tested gene-based interactions with 25(OH)D.Results: The SNP with the smallest interaction P value was rs4328262 in VDR (P = 0.0008); the 25(OH)D HR was 0.92 [95% confidence interval (CI), 0.68-1.24] among those homozygous for the common allele, and the minor allele was estimated to decrease the HR by 33% per copy (RHR = 0.67; 95% CI, 0.53-0.85). Five other VDR SNPs showed evidence of interaction at P < 0.05, as did one SNP in CYP2R1 and one in RXRA As a group, the 82 SNPs showed evidence of multiplicative interaction with 25(OH)D (P = 0.04). In gene-based tests, only VDR showed strong evidence of interaction (P = 0.04).Conclusions: SNPs in vitamin D-related genes may modify the association between serum 25(OH)D and breast cancer.Impact: This work strengthens the evidence for protective effects of vitamin D. Cancer Epidemiol Biomarkers Prev; 26(12); 1761-71. ©2017 AACR.

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.

Vitamin D metabolites in captivity? Should we measure free or total 25(OH)D to assess vitamin D status?

There is general consensus that serum 25(OH)D is the best biochemical marker for nutritional vitamin D status. Whether free 25(OH)D would be a better marker than total 25(OH)D is so far unclear. Free 25(OH)D can either be calculated based on the measurement of the serum concentrations of total 25(OH)D, vitamin D-binding protein (DBP), albumin, and the affinity between 25(OH)D and its binding proteins in physiological situations. Free 25(OH)D can also be measured directly by equilibrium dialysis, ultrafitration or immunoassays. During the vitamin D workshop held in Boston in March 2016, a debate was organized about the measurements and clinical value of free 25(OH)D, and this debate is summarized in the present manuscript. Overall there is consensus that most cells apart from the renal tubular cells are exposed to free rather than to total 25(OH)D. Therefore free 25(OH)D may be highly relevant for the local production and action of 1,25(OH)₂D. During the debate it became clear that there is a need for standardization of measurements of serum DBP and of direct measurements of free 25(OH)D. There seems to be very limited genetic or racial differences in DBP concentrations or (probably) in the affinity of DBP for its major ligands. Therefore, free 25(OH)D is strongly correlated to total 25(OH)D in most normal populations. Appropriate studies are needed to define the clinical implications of free rather than total 25(OH)D in normal subjects and in disease states. Special attention is needed for such studies in cases of abnormal DBP concentrations or when one could expect changes in its affinity for its ligands.

Vitamin D receptor polymorphisms or serum levels as key drivers of breast cancer development? The question of the vitamin D pathway

As total vitamin D levels are often lower in black than in white Americans, the former are frequently classified as vitamin D-deficient. To fully understand African vitamin D (25(OH)D) status, other factors should be considered, e.g. vitamin D blood carrier, vitamin D-binding protein (DBP), vitamin D receptor (VDR) and DBP polymorphisms. A prospective study on an indigenous black Tanzanian and a Caucasian Italian population was performed on 50 healthy donors from both populations and 35 Caucasian and 18 African breast cancer patients. 25(OH)D and DBP serum levels were analyzed by ELISA. A1012G, Cdx2 and Fok1 VDR polymorphisms and DBP polymorphisms rs4588 and rs7041 were genotyped by real-time PCR. Vitamin D and DBP levels were lower in healthy African donors than in Caucasians. Africans had a significantly higher frequency of AA and CC for Cdx2 and Fok1 polymorphisms, respectively. These allelic variants were related to a higher transcription of VDR gene and a higher activity of VDR receptor. With regard to polymorphism distribution, Africans showed innate higher levels and activity of VDR. We conclude that a strengthening of the vitamin D pathway could have a protective role against the development of breast cancer in the African population.

Phytotherapy and Nutritional Supplements on Breast Cancer

Breast cancer is the most frequent type of nonskin malignancy among women worldwide. In general, conventional cancer treatment options (i.e., surgery, radiotherapy, chemotherapy, biological therapy, and hormone therapy) are not completely effective. Recurrence and other pathologic situations are still an issue in breast cancer patients due to side effects, toxicity of drugs in normal cells, and aggressive behaviour of the tumours. From this point of view, breast cancer therapy and adjuvant methods represent a promising and challenging field for researchers. In the last few years, the use of some types of complementary medicines by women with a history of breast cancer has significantly increased such as phytotherapeutic products and nutritional supplements. Despite this, the use of such approaches in oncologic processes may be problematic and patient's health risks can arise such as interference with the efficacy of standard cancer treatment. The present review gives an overview of the most usual phytotherapeutic products and nutritional supplements with application in breast cancer patients as adjuvant approach. Regardless of the contradictory results of scientific evidence, we demonstrated the need to perform additional investigation, mainly well-designed clinical trials in order to establish correlations and allow for further validated outcomes concerning the efficacy, safety, and clinical evidence-based recommendation of these products.

The impact of vitamin D pathway genetic variation and circulating 25-hydroxyvitamin D on cancer outcome: systematic review and meta-analysis

BACKGROUND

Vitamin D has been linked with improved cancer outcome. This systematic review and meta-analysis investigates the relationship between cancer outcomes and both vitamin D-related genetic variation and circulating 25-hydroxyvitamin D (25OHD) concentration.

METHODS

A systematic review and meta-analysis of papers until November 2016 on PubMed, EMBASE and Web of Science pertaining to association between circulating vitamin D level, functionally relevant vitamin D receptor genetic variants and variants within vitamin D pathway genes and cancer survival or disease progression was performed.

RESULTS

A total of 44 165 cases from 64 studies were included in meta-analyses. Higher 25OHD was associated with better overall survival (hazard ratio (HR=0.74, 95% CI: 0.66-0.82) and progression-free survival (HR=0.84, 95% CI: 0.77-0.91). The rs1544410 (BsmI) variant was associated with overall survival (HR=1.40, 95% CI: 1.05-1.75) and rs7975232 (ApaI) with progression-free survival (HR=1.29, 95% CI: 1.02-1.56). The rs2228570 (FokI) variant was associated with overall survival in lung cancer patients (HR=1.29, 95% CI: 1.0-1.57), with a suggestive association across all cancers (HR=1.26, 95% CI: 0.96-1.56).

CONCLUSIONS

Higher 25OHD concentration is associated with better cancer outcome, and the observed association of functional variants in vitamin D pathway genes with outcome supports a causal link. This analysis provides powerful background rationale to instigate clinical trials to investigate the potential beneficial effect of vitamin D in the context of stratification by genotype.

Single nucleotide polymorphisms in the vitamin D pathway associating with circulating concentrations of vitamin D metabolites and non-skeletal health outcomes: Review of genetic association studies

Polymorphisms in genes encoding proteins involved in vitamin D metabolism and transport are recognised to influence vitamin D status. Syntheses of genetic association studies linking these variants to non-skeletal health outcomes are lacking. We therefore conducted a literature review to identify reports of statistically significant associations between single nucleotide polymorphisms (SNP) in 11 vitamin D pathway genes (DHCR7, CYP2R1, CYP3A4, CYP27A1, DBP, LRP2, CUB, CYP27B1, CYP24A1, VDR and RXRA) and non-bone health outcomes and circulating levels of 25-hydroxyvitamin D (25[OH]D and 1,25-dihydroxyvitamin D (1,25[OH]₂D). A total of 120 genetic association studies reported positive associations, of which 44 investigated determinants of circulating 25(OH)D and/or 1,25(OH)₂D concentrations, and 76 investigated determinants of non-skeletal health outcomes. Statistically significant associations were reported for a total of 55 SNP in the 11 genes investigated. There was limited overlap between genetic determinants of vitamin D status and those associated with non-skeletal health outcomes: polymorphisms in DBP, CYP2R1 and DHCR7 were the most frequent to be reported to associate with circulating concentrations of 25(OH)D, while polymorphisms in VDR were most commonly reported to associate with non-skeletal health outcomes, among which infectious and autoimmune diseases were the most represented.

Meta-analysis on vitamin D receptor and cancer risk: focus on the role of TaqI, ApaI, and Cdx2 polymorphisms

Vitamin D plays a significant role in our health, including cancer incidence and mortality. Vitamin D receptor (VDR) single-nucleotide polymorphisms (SNPs) may affect its activity, influencing the risk of cancer. Several studies have investigated VDR SNPs, but the association with the risk of cancer is controversial. Here, we present a meta-analysis to assess the association of TaqI, ApaI, and Cdx2 SNPs with the risk of cancer. A systematic literature search was performed following a predefined protocol and using validated search strategies. This meta-analysis shows the summary odd ratio (SOR) overall, by cancer sites and by ethnicity. Up to January 2014, we identified 73 independent studies with 35 525 cases and 38 675 controls. The meta-analysis of Cdx2 gg versus GG showed a significant 12% increased risk for all cancers [SOR=1.12; 95% confidence interval (CI): 1.00–1.25]. The other SNPs analyzed did not show an overall significant association with the risk of cancer: SOR=0.98 (95% CI: 0.90–1.07) and 1.06 (95% CI: 0.95–1.19) for TaqI tt versus TT and ApaI aa versus AA, respectively. TaqI shows a significant 43% increased risk for colorectal cancer (SOR=1.43; 95% CI: 1.30–1.58 for tt vs. TT). Strong frequency variations are present among different ethnic groups. This meta-analysis showed an overall increased risk of cancer associated with Cdx2 SNP and a specific higher risk of colorectal cancer associated with the TaqI polymorphism. The VDR genotype might become more relevant when clustered in a specific haplotype, associated with other SNPs of genes involved in vitamin D metabolism, or for specific tumors and/or patient characteristics.

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.

Weight Status and Alcohol Intake Modify the Association between Vitamin D and Breast Cancer Risk

BACKGROUND

Mechanistic hypotheses suggest that vitamin D may contribute to the prevention of breast cancer. However, epidemiologic evidence is inconsistent, suggesting a potential effect modification by individual factors.

OBJECTIVE

Our objective was to perform exploratory analyses on the prospective associations between the plasma 25-hydroxyvitamin D [25(OH)D] concentration, polymorphisms of genes encoding for the vitamin D receptor (VDR) and vitamin D-binding protein (also known as gc-globulin or group-specific component, GC), and breast cancer risk, along with 2 potential modifiers: body mass index (BMI; in kg/m(2)) and alcohol intake.

METHODS

A nested case-control study was set up in the SUpplémentation en VItamines et Minéraux Anti-oXydants (SU.VI.MAX) cohort (1994-2007), involving 233 women with breast cancer and 466 matched controls (mean ± SD age: 49 ± 6 y). The plasma total 25(OH)D concentration and gene polymorphisms were assessed on samples obtained at baseline. Conditional logistic regression models were computed.

RESULTS

A higher plasma 25(OH)D concentration was associated with a decreased risk of breast cancer for women with a BMI < the median of 22.4 [OR quartile (Q)4 compared with Q1: 0.46; 95% CI: 0.23, 0.89; P-trend = 0.01, P-interaction = 0.002], whereas it was associated with an increased risk for women with a BMI ≥ the median (OR Q4 compared with Q1: 2.45; 95% CI: 1.13, 5.28; P-trend = 0.02, P-interaction = 0.002). A plasma 25(OH)D concentration ≥ 10 ng/mL was associated with a decreased risk of breast cancer for women with alcohol intakes ≥ the median of 7.1 g/d (OR ≥10 compared with <10 ng/mL: 0.50; 95% CI: 0.26, 0.95; P = 0.03, P-interaction = 0.03). The genetic analyses were consistent with the results observed with plasma 25(OH)D.

CONCLUSION

In this prospective study, BMI and alcohol intake modified the association between vitamin D [plasma 25(OH)D and vitamin D-related gene polymorphisms] and breast cancer risk. These effect modifications suggest explanations for discrepancies in results of previous studies. This trial was registered at clinicaltrials.gov as NCT00272428.

Single nucleotide polymorphisms in the Gc gene for vitamin D binding protein in common cancers in Thailand

BACKGROUND

This case-control study aimed to determine if there were any associations between the two single nucleotide polymorphisms (SNPs) in Gc, rs7041 (Asp416Glu) and rs4588 (Thr420Lys) and 3 common cancers (breast, lung and colorectal) in Thai patients.

MATERIALS AND METHODS

Two hundred and eighty two colorectal, 101 breast and 113 lung cancer patients were recruited from one institute during 2011-2013. The controls were age-matched volunteers who had a negative history of index cancers. In addition, vitamin D levels were compared among different genotypes in the 2 SNPs.

RESULTS

The minor allele frequencies of rs7041 (G) and rs4588 (A) were 0.32 and 0.24, respectively. Under the dominant model, the study found significant associations between minor-allele genotypes of the SNP rs7041 (TG/GG) and lung cancer (odds ratio [OR] 1.78, 95% CI 1.05-3.03). When subgroup analysis was performed according to sex and age at diagnosis, the study found that the minor- allele genotypes of rs7041 (TG/GG) were significantly associated with colorectal cancer in patients whose age at diagnosis was more than 60 years (OR 1.67, 95%CI 1.06-2.61) and the minor-allele genotypes of rs4588 (CA/AA) were significantly associated with colorectal cancer in males aged 60 years or less (OR 2.34, 95%CI 1.25-4.37). When SNP combinations (rs7041-rs4588) were examined, the TT-CA combination had a significant protective association with lung cancer (OR 0.44, 95% CI 0.22-0.85). On evaluation of serum 25(OH)D levels in 205 individuals without cancer (males 144, females 61), the proportion of subjects with low serum vitamin D (< 20 ng/ml) in those harboring CA or AA genotypes of rs4588 (41.7%) was significantly higher than the CC genotype (15.5%, p-value < 0.01).

CONCLUSIONS

Genetic polymorphisms in Gc were associated with lung and colorectal cancers in Thai patients. Lower serum 25(OH)D in minor variants of rs4588 may explain this association.

Genetic polymorphisms in the vitamin D pathway in relation to lung cancer risk and survival

Studies have suggested that vitamin D may have protective effects against cancer development or tumor progression. To search for additional evidence, we investigated the role of genetic polymorphisms involved in the vitamin D pathway in non-small cell lung cancer (NSCLC). We evaluated common genetic polymorphisms associated with the vitamin D pathway in relation to NSCLC in a case-control study of 603 newly diagnosed NSCLC patients and 661 matched healthy controls. Seven single nucleotide polymorphisms (SNPs) were genotyped, the expression of CYP27B1 and CYP24A1 were measured in 153 tumor samples and their associations with genotypes and patient survival were also analyzed. In the case-control comparison, we found SNP rs3782130 (CYP27B1), rs7041 (GC), rs6068816 and rs4809957 (CYP24A1) associated with NSCLC risk. The risk of NSCLC was increased with the number of risk alleles. CYP27B1 and CYP24A1 expression were significantly different between tumor and normal tissues in NSCLC. High CYP27B1 expression was associated with better overall survival, and the expression was different by the rs3782130 genotype. The study suggests that some genetic polymorphisms involved in the vitamin D pathway may associate with NSCLC risk, and one of the polymorphisms (rs3782130) may affect gene expression and patient survival.

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.

Genetic Polymorphisms in Vitamin D Metabolism and Signaling Genes and Risk of Breast Cancer: A Nested Case-Control Study

Genetic polymorphisms in vitamin D metabolism and signaling genes have been inconsistently associated with risk of breast cancer, though few studies have examined SNPs in vitamin D-related genes other than the vitamin D receptor (VDR) gene and particularly have not examined the association with the retinoid X receptor alpha (RXRA) gene which may be a key vitamin D pathway gene. We conducted a nested case-control study of 734 cases and 1435 individually matched controls from a population-based prospective cohort study, the Northern Sweden Mammary Screening Cohort. Tag and functional SNPs were genotyped for the VDR, cytochrome p450 24A1 (CYP24A1), and RXRA genes. We also genotyped specific SNPs in four other genes related to vitamin D metabolism and signaling (GC/VDBP, CYP2R1, DHCR7, and CYP27B1). SNPs in the CYP2R1, DHCR7, and VDBP gene regions that were associated with circulating 25(OH)D concentration in GWAS were also associated with plasma 25(OH)D in our study (p-trend <0.005). After taking into account the false discovery rate, these SNPs were not significantly associated with breast cancer risk, nor were any of the other SNPs or haplotypes in VDR, RXRA, and CYP24A1. We observed no statistically significant associations between polymorphisms or haplotypes in key vitamin D-related genes and risk of breast cancer. These results, combined with the observation in this cohort and most other prospective studies of no association of circulating 25(OH)D with breast cancer risk, do not support an association between vitamin D and breast cancer risk.

Meta-analysis of vitamin D-binding protein and cancer risk

BACKGROUND

Epidemiologic evidence supported a role for vitamin D and vitamin D receptor (VDR) polymorphisms in cancer risk. Beyond VDR, the biologic effects of vitamin D are mediated by the vitamin D-binding protein (DBP), a key protein in vitamin D metabolism. Furthermore, the gene encoding the DBP (GC, group-specific component) has an important role in the vitamin D pathway. Several studies investigated DBP serologic levels and GC polymorphisms in association with cancer risk with controversial results. Thus, we carried out a meta-analysis to investigate these associations.

METHODS

We included 28 independent studies concerning the following tumors: basal cell carcinoma, bladder, breast, colon-rectum, endometrium, liver, esophagus, stomach, melanoma, pancreas, prostate, and kidney. Through random-effect models, we calculated the summary odds ratios (SOR) for serum DBP and the GC polymorphisms rs2282679, rs12512631, rs7041, rs4588, rs17467825, rs1155563, and rs1352844.

RESULTS

We found a borderline decrease in cancer risk for subjects with high compared with low levels of DBP [SOR, 0.75; 95% confidence interval (CI), 0.56-1.00]. Dose-response meta-analysis indicates a nonsignificant decrease risk for an increase of 1,000 nmol/L of DBP (SOR, 0.96; 95% CI, 0.91-1.01). We found no significant alterations in cancer risk for subjects carrying any of the studied GC polymorphisms compared with wild-type subjects both in the main analysis and in analyses stratified by cancer type and ethnicity.

CONCLUSIONS

We found trends toward significance, suggesting a role of DBP in cancer etiology, which should be confirmed in further studies.

IMPACT

To our knowledge, this is the first study to investigate GC polymorphisms and DBP serologic levels in association with any type of cancer.

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.

Association of Vitamin D Receptor Cdx-2 Polymorphism With Cancer Risk: A Meta-Analysis

Vitamin D receptor (VDR) Cdx-2 polymorphism (rs11568820) has been indicated to be associated to cancer susceptibility. However, published studies reported mixed results. This meta-analysis was conducted to get a more accurate estimation of the association between Cdx-2 polymorphism and cancer risk.We identified 25 independent studies with a total of 34,018 subjects published prior to March 2015. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the susceptibility to cancer. Separate analyses were conducted on features of the population such as ethnicity, source of controls, and cancer types.Meta-analysis results showed that Cdx-2 polymorphism significantly increased cancer risk in the homozygous model in overall analysis. According to the further stratified analysis, significant association was found between Cdx-2 variant and cancer risk in American-Africans in the homozygous, recessive, and dominant comparison models. However, no significant associations were found in Caucasians and Asians. When stratified by different cancer types, significant association was observed between Cdx-2 variant and an increased risk of colorectal cancer in the homozygous, recessive, and dominant models. In addition, ovarian cancer susceptibility increased based on the homozygous and dominant comparison models.Our study indicated that VDR Cdx-2 polymorphism was associated with an increased cancer risk, particularly in American-Africans, colorectal, and ovarian cancers. However, other factors may impact on the association. Further multicenter studies are needed to confirm the effects of Cdx-2 polymorphism on cancer susceptibility.

Will Women Diagnosed with Breast Cancer Provide Biological Samples for Research Purposes?

BACKGROUND

Little is known about the response rates for biological sample donation and attitudes towards control recruitment, especially in younger women. The goals of this pilot study were to determine in women recently diagnosed with breast cancer, the proportion of cases willing to provide biological samples and for purposes of control recruitment, contact information for friends or colleagues.

METHODS

A population-based sample of breast cancer cases (n = 417, 25-74 years) was recruited from the Ontario Cancer Registry in 2010 and self-administered questionnaires were completed to determine willingness to provide samples (spot or 24-hr urine, saliva, blood) and contact information for friends/colleagues for control recruitment. Using Χ2 analyses of contingency tables we evaluated if these proportions varied by age group (<45 and 45+) and other factors such as ethnicity, education, income, body mass index (BMI), smoking status and alcohol consumption.

RESULTS

Cases were willing to provide blood samples, by visiting a clinic (62%) or by having a nurse visit the home (61%). Moreover, they would provide saliva (73%), and morning or 24-hr urine samples (66% and 52%). Younger cases (≤45) were 3 times (OR) more likely more than older cases to agree to collect morning urine (95% CI: 1.15-8.35). Only 26% of cases indicated they would provide contact information of friends or work colleagues to act as controls. Educated cases were more likely to agree to provide samples, and cases who consumed alcohol were more willing to provide contact information. Ethnicity, income, BMI and smoking had little effect on response rates.

CONCLUSIONS

Reasonable response rates for biological sample collection should be expected in future case controls studies in younger women, but other methods of control selection must be devised.