Comprehensive association analysis of the vitamin D pathway genes, VDR, CYP27B1, and CYP24A1, in prostate cancer

1,25-Dihydroxyvitamin D3 Suppresses Prognostic Survival Biomarkers Associated with Cell Cycle and Actin Organization in a Non-Malignant African American Prostate Cell Line

Vitamin D3 is a steroid hormone that confers anti-tumorigenic properties in prostate cells. Serum vitamin D3 deficiency has been associated with advanced prostate cancer (PCa), particularly affecting African American (AA) men. Therefore, elucidating the pleiotropic effects of vitamin D on signaling pathways, essential to maintaining non-malignancy, may provide additional drug targets to mitigate disparate outcomes for men with PCa, especially AA men. We conducted RNA sequencing on an AA non-malignant prostate cell line, RC-77N/E, comparing untreated cells to those treated with 10 nM of vitamin D3 metabolite, 1α,25(OH)2D3, at 24 h. Differential gene expression analysis revealed 1601 significant genes affected by 1α,25(OH)2D3 treatment. Pathway enrichment analysis predicted 1α,25(OH)2D3- mediated repression of prostate cancer, cell proliferation, actin cytoskeletal, and actin-related signaling pathways (p < 0.05). Prioritizing genes with vitamin D response elements and associating expression levels with overall survival (OS) in The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA PRAD) cohort, we identified ANLN (Anillin) and ECT2 (Epithelial Cell Transforming 2) as potential prognostic PCa biomarkers. Both genes were strongly correlated and significantly downregulated by 1α,25(OH)2D3 treatment, where low expression was statistically associated with better overall survival outcomes in the TCGA PRAD public cohort. Increased ANLN and ECT2 mRNA gene expression was significantly associated with PCa, and Gleason scores using both the TCGA cohort (p < 0.05) and an AA non-malignant/tumor-matched cohort. Our findings suggest 1α,25(OH)2D3 regulation of these biomarkers may be significant for PCa prevention. In addition, 1α,25(OH)2D3 could be used as an adjuvant treatment targeting actin cytoskeleton signaling and actin cytoskeleton-related signaling pathways, particularly among AA men.

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.

Vitamin D is a potential treatment for the management of gastrointestinal mucositis

PURPOSE OF THE REVIEW

Gastrointestinal mucositis (GM) is a severe side effect of cancer treatments, negatively impacting the patient's quality of life, and has limited treatment. GM consists of complex biological processes involving apoptosis and inflammation, leading to damage and ulceration of the gastrointestinal system. Recently, vitamin D has been shown to have multiple roles in the gut, including immunomodulation, epithelial barrier regulation and microbiome regulation. Hence, this review aims to put forth vitamin D as a potential therapeutic due to its protective role in the intestine.

RECENT FINDINGS

Recent studies have shown that vitamin D can reduce intestinal inflammation by reducing NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation. Vitamin D also targets and maintains the intestinal epithelial barrier via the tight junction protein expression and the inhibition of microbiome translocation. Significant evidence also suggests that vitamin D exerts multiple therapeutic effects through binding to vitamin D receptors (VDRs), and the downregulation of VDR has been associated with the severity of the disease. Additionally, vitamin D deficiency is reported in cancer patients.

SUMMARY

There is a dire need for effective treatment for GM, and recent animal and human studies show that vitamin D may be a potential therapy to prevent or treat GM.

Role of purinergic system and vitamin D in the anti-cancer immune response

For several years, scientists have recognized that vitamin D plays an important role in mineral and bone homeostasis. It was mostly used to treat osteoporosis and rickets in the past decades. Vitamin D has also been discovered to be modulator of the immune system and may play a role in a variety of diseases, including autoimmune diseases, in recent years. Vitamin D interaction with the vitamin D receptor (VDR), which has transcriptional imparts and is displayed on a variety of cell types, including those of the immune system, appears to be accountable for the immune-modulating effects. The action of tumor cells and vitamin D were the first to be investigated, but the spotlight is now on immunologic and purinergic systems. We conducted a systematic search in Pub Med as well as Google scholar for studies written in English. Vitamin D, cancer, purinergic signaling, and immune response were among the search words. Vitamin D has the potential to be a useful coadjuvant in cancer therapy and the purinergic system may be a potential treatment target to cancer therapy, according to our findings.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Vitamin D sufficiency enhances differentiation of patient-derived prostate epithelial organoids

Vitamin D is an essential steroid hormone that regulates systemic calcium homeostasis and cell fate decisions. The prostate gland is hormonally regulated, requiring steroids for proliferation and differentiation of secretory luminal cells. Vitamin D deficiency is associated with an increased risk of lethal prostate cancer, which exhibits a dedifferentiated pathology, linking vitamin D sufficiency to epithelial differentiation. To determine vitamin D regulation of prostatic epithelial differentiation, patient-derived benign prostate epithelial organoids were grown in vitamin D-deficient or -sufficient conditions. Organoids were assessed by phenotype and single-cell RNA sequencing. Mechanistic validation demonstrated that vitamin D sufficiency promoted organoid growth and accelerated differentiation by inhibiting canonical Wnt activity and suppressing Wnt family member DKK3. Wnt and DKK3 were also reduced by vitamin D in prostate tissue explants by spatial transcriptomics. Wnt dysregulation is a known contributor to aggressive prostate cancer, thus findings further link vitamin D deficiency to lethal disease.

Development of novel parameter for monitoring of malignant melanoma progression

Objective

Increasing HIFs in malignant melanoma, the highly aggressive skin tumour, results in the stimulation of invasiveness. Increased HIF-1α fallouts in inhibition of the activity of some mitochondrial enzymes and leads to preference of cytosol energetic metabolism. Increase of aerobic glycolysis is reflected in an increase of free NADH (Warburg effect) and develops the malignant melanoma.

Our goal was to find a link between hypoxia, or hypoxia mimicking factors and the stage of malignant melanoma. Furthermore, we focused on the finding of the experimental parameter which could monitor melanoma patients.

Patients and methods

We targeted HIF-1α gene expression and VDR rs2107301 gene polymorphism by PCR analysis. We detected the level of NADH in blood plasma by fluorescence spectroscopy (excitation and emission spectra).

Results

Analysis of the obtained data from patient samples has shown an increase in HIF-1α which correlates with the disease stage. Investigation VDR rs2107301 polymorphism of patient samples does not show any significant changes in single nucleotide polymorphism, and the low vitamin D level in blood is not a result of VDR mutation in mitochondria. NADH levels vary under hypoxic and pseudohypoxic conditions and refer to the cancer stage.

Conclusions

The apparent mismatch between HIF-1α expression and NADH fluorescence has become the basis for the design of an algorithm for monitoring malignant melanoma based on the sensing of NADH fluorescence and the determination of HIF-1α.

The association study between CYP24A1 gene polymorphisms and risk of liver, lung and gastric cancer in a Chinese population

Recently, four single nucleotide polymorphisms (rs2585428, rs4809960, rs6022999 and rs6068816) in CYP24A1 gene were extensively studied for their associations with cancer risk. However, these studies included only a few types of cancer, which calls for further investigations. In view of this, we here conducted a case-control study to explore the associations between these four CYP24A1 gene polymorphisms and risk of liver, lung and gastric cancer in a Chinese population. A total of 480 liver cancer patients, 550 lung cancer patients, 460 gastric cancer patients and 800 normal controls were recruited in this study. The genotyping of CYP24A1 gene polymorphisms was applied with Sanger sequencing assay. Single-locus analysis demonstrated that rs6022999 was significantly associated with risk of liver and lung cancer, while rs6068816 was significantly associated with the risk of gastric cancer. Haplotype analysis revealed that haplotype GTAT was associated with an increased risk of liver cancer and a decreased risk of lung cancer, and haplotype ATGC was associated with a decreased risk of lung cancer. The further meta-analysis of rs6068816 and lung cancer risk showed that rs6068816 was not associated with lung cancer risk in Chinese population, which confirmed our present finding. Conclusively, rs6022999 may be a genetic biomarker for liver and lung cancer susceptibility in Chinese population, and rs6068816 may be used to predict gastric cancer risk in Chinese population.

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.

25-Hydroxyvitamin D status, vitamin D intake, and skin cancer risk: a systematic review and dose-response meta-analysis of prospective studies

Sun exposure is a major environmental risk factor for skin cancers and is also an important source of vitamin D. However, while experimental evidence suggests that vitamin D may have a protective effect on skin cancer risk, epidemiologic studies investigating the influence of 25-hydroxyvitamin D (25(OH)D) level and/or vitamin D intake on skin cancer risk are conflicting. A systematic review and dose–response meta-analyses of prospective studies was conducted to clarify these associations. Relevant studies were identified by searching the PubMed database up to 30th August 2019. Random effects dose–response meta-analyses were used to estimate summary relative risks (SRRs) and 95% confidence intervals (CIs). Overall, thirteen prospective studies were included. Circulating level of 25(OH)D was associated with higher risks of melanoma (SRR (95% CI) per 30 nmol = 1.42 (1.17–1.72)) and keratinocyte cancer (KC) (SRR (95% CI) per 30 nmol/L = 1.30 (1.13–1.49)). The SRR (95% CI) per 30 nmol/L increase in 25(OH) D level was 1.41 (1.19–1.67), and 1.57 (0.64–3.86), for basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), respectively. However, while we found that vitamin D intake (from diet, supplemental and total) was not associated with risks of melanoma and SCC, vitamin D intake was associated with slightly increased BCC risk, albeit with no heterogeneity across skin cancer type. This meta-analysis suggests positive associations between circulating 25(OH)D level and risk of melanoma and KC, however, this finding is most likely confounded by sun exposure. We found no associations between vitamin D intake skin cancers, except positive associations with BCC risk.

BRCA1 and VDR gene polymorphisms are associated with prostate cancer risk in Mexican men

Prostate cancer (PC) is a polygenic disease with broad differences across ethnicities. BRCA1/2 and VDR have exhibited a featured genetic contribution to PC development in European populations. Nonetheless, its contribution in Latino populations specifically among Mexican men, where 70% of PC cases are detected in advanced stages, is still unknown. The contribution of seven polymorphisms in BRCA1/2 and VDR genes to PC susceptibility was evaluated in 370 incident PC cases and 759 age-matched (±5 years) controls belonging to the Mexican population. Based on Gleason score at diagnosis, PC cases were classified as well-differentiated PC (Gleason <7) and moderate or poorly differentiated PC (Gleason ≥7). Age at diagnosis was used to divided PC cases in earlier (<60 years) and late-onset PC (≥60 years). Prostate and breast cancer family histories were obtained through interview. Our results provided evidences about the contribution of BRCA1-rs1799966 (OR_{CC genotype}  = 2.30; 95% confidence interval [CI] = 1.36-3.91) to the moderate or poorly differentiated PC risk, independently of the family history of prostate, breast or ovary cancer. Further, VDR-rs2238135-G allele was associated with early-onset PC (OR_{G allele}  = 2.05; 95% CI = 1.06-3.95), and marginally with moderate or poorly differentiated PC risk. The present study revealed the crucial role of BRCA1 in PC aggressiveness risk, outstanding the gender imbalance regarding the breast cancer risk in women.

The Association of a Novel Identified VDR SNP With Prostate Cancer in African American Men

BACKGROUND/AIM

Vitamin D receptor (VDR) is present in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to prostate cancer. Also, analyses of single nucleotide polymorphisms (SNPs) in VDR revealed ethnicity-associated polymorphisms. The aim of this study was to identify VDR SNPs in African American men with and without prostate cancer.

MATERIALS AND METHODS

The entire VDR gene was screened for germline mutations in a case-control study by denaturing high performance liquid chromatography and DNA sequencing. Logistic regression was used to estimate the association of SNPs, age, family history, and Gleason score with prostate cancer risk.

RESULTS

Six SNPs in the non-coding regions, and one SNP in the coding region, were detected. SNP 1 (c.278-69G>A) and SNP 4 (c.907+75C>T) have not been previously reported. SNP 4 had a significant protective effect (β=-0.6, p<0.05); whereas, SNP 7 (rs7975232) showed an increase association with prostate cancer risk and high Gleason score (β=0.32, p<0.05). SNP 4, SNP 7 and age were better predictors of prostate cancer risk than family history with a high degree of sensitivity (74.7%) and specificity (92.4%).

CONCLUSION

SNP 4 and SNP 7 could be promising markers for prediction of reduced or increased prostate cancer risk, respectively.

A candidate intronic CYP24A1 gene variant affects the risk of colorectal cancer

Aim: rs2585428 and rs4809960 polymorphisms were significantly associated with overall cancer risk, but there is no evidence regarding the overall colorectal cancer (CRC) risk. Materials & methods: A total of 505 subjects, including 246 patients with CRC and 259 noncancer controls participated in the study. The genotyping was performed using tetra-primer amplification refractory mutation systems PCR. Results: Analysis of genotypes revealed that CYP24A1 rs4809960 CC genotype decreased the risk of CRC (p = 0.009). In addition, the genotype frequencies showed a significant difference under the dominant and recessive inheritance models (p = 0.019 and p = 0.02, respectively). Conclusion: Our findings indicate that the CYP24A1 rs4809960 polymorphism decreased the risk of CRC in the studied population.

Association study between CYP24A1 gene polymorphisms and cancer risk

CYP24A1, an essential gene in regulation of vitamin D, has been reported to play an important role in enhancing immune activity and inhibiting tumorigenesis. Previous studies proposed that rs2585428, rs4809960, rs6022999 and rs6068816 in CYP24A1 gene might be greatly associated with cancer risk. To validate the findings, we here investigated the associations of these four polymorphisms and colorectal cancer (CRC) risk in a central Chinese population (426 colon cancer patients, 361 rectal cancer patients and 800 healthy controls). The genotyping was conducted by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and confirmed by sequencing. Our results revealed that the rs4809960 and rs6022999 were strongly associated with the CRC risk, especially with the colon cancer risk. Moreover, the analysis of haplotypes consisting of rs2585428(G > A), rs4809960(T > C), rs6022999(A > G) and rs6068816(C > T) indicated that haplotype ATGC significantly decreased the CRC risk, especially the colon cancer risk. Haplotype GCAT significantly increased the CRC risk, especially the rectal cancer risk. However, haplotype ACAC was only found to be associated with increased risk of CRC. To improve the statistical strength, an updated meta-analysis was further performed. The results showed that rs2585428 was associated with cancer risk in Caucasian population, rs4809960 was associated with breast cancer risk in Caucasian population, and rs6022999 was associated with cancer risk in Asian population. Collectively, the rs4809960 and rs6022999 may be the genetic biomarkers for prediction of colon cancer risk in Chinese population, the rs2585428 and rs6022999 may link to cancer susceptibility in Caucasian population and in Asian population respectly.

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.

Role of Key Micronutrients from Nutrigenetic and Nutrigenomic Perspectives in Cancer Prevention

Regarding cancer as a genetic multi-factorial disease, a number of aspects need to be investigated and analyzed in terms of cancer's predisposition, development and prognosis. One of these multi-dimensional factors, which has gained increased attention in the oncological field due to its unelucidated role in risk assessment for cancer, is diet. Moreover, as studies advance, a clearer connection between diet and the molecular alteration of patients is becoming identifiable and quantifiable, thereby replacing the old general view associating specific phenotypical changes with the differential intake of nutrients. Respectively, there are two major fields concentrated on the interrelation between genome and diet: nutrigenetics and nutrigenomics. Nutrigenetics studies the effects of nutrition at the gene level, whereas nutrigenomics studies the effect of nutrients on genome and transcriptome patterns. By precisely evaluating the interaction between the genomic profile of patients and their nutrient intake, it is possible to envision a concept of personalized medicine encompassing nutrition and health care. The list of nutrients that could have an inhibitory effect on cancer development is quite extensive, with evidence in the scientific literature. The administration of these nutrients showed significant results in vitro and in vivo regarding cancer inhibition, although more studies regarding administration in effective doses in actual patients need to be done.

Vitamin D and overall cancer risk and cancer mortality: a Mendelian randomization study

There is considerable debate regarding the role that 25-hydroxyvitamin D [25(OH)D] concentrations play in cancer risk or mortality, with earlier studies drawing mixed conclusions. Using data from the UK Biobank (UKB), we evaluate whether genetically predicted 25(OH)D concentrations are associated with overall cancer susceptibility and cancer mortality using five 25(OH)D genetic markers. Data comprised 438 870 white British UKB participants aged 37-73, including 46 155 cancer cases and 6998 cancer-specific deaths. Participants with keratinocyte cancers and/or benign tumors were excluded from the analysis. Odds ratios were calculated per 20 nmol/L increase in genetically predicted 25(OH)D for cancer risk and cancer mortality. For individual cancer risks, estimates were meta-analyzed with publicly available data using a fixed-effect inverse-variance-weighted model. We demonstrated that genetically low plasma 25(OH)D concentrations were not associated with increased cancer risk nor cancer mortality. Stratification by sex or cancer types did not reveal any meaningful differences albeit wider confidence intervals. Fixed-effect meta-analysis of our individual cancer risk estimates with those derived from publicly available cancer consortia data and previous studies further reinforced our null Mendelian randomization findings on prostate, lung, colorectal and breast cancers with tight confidence intervals; for ovarian and pancreatic cancers, our estimates were less precise despite being not statistically significant. Taken altogether, our results provide no genetic evidence for an association between vitamin D and overall cancer outcomes, with tight confidence intervals to exclude all but very small effect sizes.

Vitamin D metabolic loci and preeclampsia risk in multi-ethnic pregnant women

Allelic variants in vitamin D metabolism genes may increase the risk of preeclampsia, but few studies have systematically tested this hypothesis. Our objective was to evaluate the relationship between maternal allelic variants in three vitamin D metabolism genes and risk of preeclampsia. Samples were from two case‐control studies of pregnant women who delivered in Pittsburgh, PA from 1999 to 2010 and twelve recruiting sites across the United States from 1959 to 1965. Single‐nucleotide polymorphisms (SNPs) were genotyped 50 kilobases up‐ and down‐stream in three genes (VDR,GC, and CYP27B1) in the samples from both studies, for a total of 744 preeclampsia cases and 2411 controls. Using multivariable logistic regression, we estimated the associations between allelic variation in each locus and preeclampsia risk by maternal race and study. Meta‐analysis was used to estimate the association across race‐study groups for each SNP. Minor allele of a noncoding region of the VDR gene was significantly associated with preeclampsia risk, which was verified in the meta‐analysis [odds ratio (OR), 95% confidence intervals (CI)] after adjusting for multiple comparisons [rs12831006:1.5 (1.2, 2.0), P < 0.0001]. The meta‐analysis identified associations for one intron GC variant [rs843010:1.4 (1.1, 1.9) P < 0.05] and two variants of the flanking region of GC [rs842991:1.5 (1.1, 2.0) P < 0.05; rs16846876:0.75 (0.58, 0.98) P < 0.05]. There were no statistically significant associations for CYP27B1 SNPs. Our results provide additional support for a biological role of vitamin D in preeclampsia.

Association of Vitamin D Receptor Polymorphisms With Activity of Acromegaly, Vitamin D Status and Risk of Osteoporotic Fractures in Acromegaly Patients

Introduction: The vitamin D receptor (VDR) gene is one of the most widely studied tumorigenesis-related genes. The primary objective of this study was assessment of possible roles of VDR gene polymorphisms in acromegaly, with regard to the activity of the disease and compared them with a control group. Furthermore, we have assessed the associations between these polymorphisms with vitamin D status as well as with TBS (trabecular bone score) and risk for osteoporotic fracture in acromegaly patients. Materials and Methods: We studied 69 patients with acromegaly and 51 healthy controls (CG). Acromegaly patients were divided into three subgroups on the basis of disease activity (AA, active acromegaly; CD, controlled disease; CA, cured acromegaly). In all patients, blood samples were obtained to assess the hormonal and metabolic status as well as genetic analysis. VDR polymorphisms were determined by means of two methods, Polymerase Chain Reactions (PCR) and minisequencing (SNaPshot). Results: Genotype frequencies for VDR ApaI, TaqI, BsmI, and FokI polymorphisms did not deviate significantly from Hardy-Weinberg equilibrium (HWE) in the acromegaly group as well as in the control group. There was no statistically significant difference in distributions of these four VDR genotypes between acromegaly patients and the control group. This study revealed statistically significant negative correlation between risk of major osteoporotic fractures and genotypes tt (TaqI), aa (ApaI) and bb (BsmI) in acromegaly groups. Furthermore, the negative correlations were observed between TBS and risk for major osteoporotic fractures and hip fractures. Conclusions: Our study suggests that tt (TaqI), aa (ApaI) and bb (BsmI) of VDR gene may be associated with better bone quality and microarchitecture (higher TBS), which lead to a lower risk of osteoporotic fractures in acromegaly patients. TBS may be a useful tool for predicting risk of fractures in acromegaly patients.

Scalable Bayesian variable selection for structured high-dimensional data

Variable selection for structured covariates lying on an underlying known graph is a problem motivated by practical applications, and has been a topic of increasing interest. However, most of the existing methods may not be scalable to high-dimensional settings involving tens of thousands of variables lying on known pathways such as the case in genomics studies. We propose an adaptive Bayesian shrinkage approach which incorporates prior network information by smoothing the shrinkage parameters for connected variables in the graph, so that the corresponding coefficients have a similar degree of shrinkage. We fit our model via a computationally efficient expectation maximization algorithm which scalable to high-dimensional settings ( p ∼ 100 , 000 ). Theoretical properties for fixed as well as increasing dimensions are established, even when the number of variables increases faster than the sample size. We demonstrate the advantages of our approach in terms of variable selection, prediction, and computational scalability via a simulation study, and apply the method to a cancer genomics study.

Vitamin D and Influenza-Prevention or Therapy?

Vitamin D generates many extraskeletal effects due to the vitamin D receptor (VDR) which is present in most tissues throughout the body. The possible role of vitamin D in infections is implied from its impact on the innate and adaptive immune responses. A significant effect is also the suppression of inflammatory processes. Because vitamin D could be acknowledged as a “seasonal stimulus”, as defined by R. Edgar Hope-Simpson, it would be crucial to prove it from a potential easy and cheap prophylaxis or therapy support perspective as far as influenza infections are concerned. The survey of the literature data generates some controversies and doubts about the possible role of vitamin D in the prevention of influenza virus. The most important point is to realise that the broad spectrum of this vitamin’s activity does not exclude such a possibility. According to most of the authors, more randomized controlled trials with effective, large populations are needed to explore the preventive effect of vitamin D supplementation on viral influenza infections.

Lack of association between the risk of prostate cancer and vitamin D receptor Bsm I polymorphism: a meta-analysis of 27 published studies

BACKGROUND

The association between vitamin D receptor gene Bsm I (rs1544410) polymorphism and prostate cancer (PCa) risk has been investigated by numerous previous studies, which yielded inconsistent results. We conducted this meta-analysis to derive a relatively precise description of this association.

METHODS

All studies published up to December 2017 were identified via a systematic search of PubMed, Embase, and China National Knowledge Infrastructure databases. Pooled odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated to describe the strength of the relationship between Bsm I and PCa risk.

RESULTS

In this meta-analysis, 27 studies with 9,993 cases and 9,345 controls were included. The pooled results revealed that Bsm I polymorphism was not associated with PCa risk in the overall analysis. Moreover, no significant relationship was found in the subgroup analyses by ethnicities, genotyping methods, Hardy-Weinberg equilibrium status, and Gleason score. In the stratified analysis by the source of controls and clinical stages, controls of benign prostatic hyperplasia (BPH) seemed to be in the particular groups in which the association of PCa risk with Bsm I polymorphism was significant (Bb vs. bb: OR=0.643, 95% CI=0.436-0.949, p=0.026; BB/Bb vs. bb: OR=0.627, 95% CI=0.411-0.954, p=0.029; B vs. b: OR=0.715, 95% CI=0.530-0.965, p=0.029).

CONCLUSION

Our results suggest that Bsm I polymorphism is weakly associated with PCa risk, and hence, it cannot be considered as a predictor of the occurrence and development of PCa in clinical practice. Future studies with a larger number of samples are needed to verify our results.

Polymorphisms of VDR gene and risk of gastric cardiac adenocarcinoma in Chinese population

Vitamin D receptor (VDR) gene polymorphisms have been reported to increase susceptibility to some malignant tumors, yet the effect on gastric cardiac adenocarcinoma susceptibility remains unknown. Here, we conducted a hospital-based case-control study to examine the correlation of single nucleotide polymorphisms of VDR rs2107301T>C, rs2228570C>T, rs1989969C>T and rs11568820 G>A and gastric cardiac adenocarcinoma susceptibility. A total 330 cases and 608 controls were enrolled in the study. Using ligation detection reaction, we found that the variant alleles of the four polymorphisms were not associated with risk of gastric cardiac adenocarcinoma. Further stratified analyses showed that there was an increased risk associated with VDR rs1989969 polymorphism among patients who were drinking or aged <60. The haplotypes VDR T_rs2107301T_rs2228570C_rs1989969G_rs11568820 reduced the susceptibility. This study demonstrated that VDR rs1989969 polymorphism was involved in the carcinogenesis of gastric cardiac adenocarcinoma, especially increased the risk in the younger and alcohol drinking Chinese population.

Vitamin D and Cancer Risk and Mortality: State of the Science, Gaps, and Challenges

There has been substantial enthusiasm recently regarding the potential role of vitamin D in the primary and secondary prevention of cancer. Laboratory studies demonstrate a range of anticarcinogenic effects for vitamin D compounds, but human studies have yielded little consistent evidence supporting a protective association. Higher circulating levels of vitamin D (i.e., 25-hydroxyvitamin D or 25(OH)D) appear to be associated with reduced risk of colorectal and bladder malignancies, but higher risk of prostate and possibly pancreatic cancers, with no clear association for most other organ sites examined. Despite there being no official institutional recommendations regarding the use of vitamin D supplements for cancer prevention, screenings for vitamin D deficiency and vitamin D supplement use have increased substantially over the past decade. These widespread practices demonstrate that population sociobehavioral changes are often adopted before scientifically well-informed policies and recommendations are available. This review critically examines the currently available epidemiologic literature regarding the associations between circulating 25(OH)D, vitamin D supplementation, and vitamin D-related genetic variation and cancer risk and mortality, with a particular emphasis on prospective studies. We identify several important gaps in our scientific knowledge that should be addressed in order to provide sufficient reproducible data to inform evidence-based recommendations related to optimal 25(OH)D concentrations (and any role for vitamin D supplementation) for the primary and secondary prevention of cancer. With few exceptions, such recommendations cannot be made at this time.

Expression Analysis of Vitamin D Signaling Pathway Genes in Epileptic Patients

Vitamin D deficiency has been detected in epileptic patients. Vitamin D participates in neuroprotection, brain cell proliferation, and differentiation. Consequently, vitamin D supplementation has been suggested as an alternative treatment in epileptic patients. We aimed at assessment of vitamin D signaling pathway in epileptic patients. In the present study, we evaluated vitamin D serum concentration as well as expression of vitamin D receptor (VDR) gene and genes encoding for vitamin D activating enzyme 1-alpha-hydroxylase (CYP27B1) and deactivating enzyme 24-hyroxylase (CYP24A1) in epileptic patients compared with healthy individuals. We found significant lower levels of vitamin D in epileptic patients compared with healthy subjects. Expression analyses showed significant downregulation of VDR expression in peripheral blood of epileptic patients compared with healthy subjects (relative expression (REx) = 0.16, P < 0.001). However, there was no significant difference in CYP24A1 expression between epileptic patients and normal subjects. CYP27B1 expression analysis showed significant upregulation in male patients aged between 30 and 40 (REx = 5.43, P = 0.013). After using two-way ANCOVA for adjusting the effects of sex and age, there was a statistically significant difference in the VDR expression values between patient and control groups (P < 0.001). Spearman's correlation analysis showed no significant correlation between genes expression levels and patients' age or vitamin D serum concentrations. However, we found significant correlations between VDR expression levels and CYP24A1/ CYP27B1 expression levels in epileptic patients (r = 0.435 and P < 0.001; r = 0.26 and P = 0.02 respectively). There was also a significant correlation between the expression levels of CYP24A1 and CYP27B1 (r = 0.349 and P = 0.001). Our study shows a possible role for VDR in the pathogenesis of epilepsy.

Vitamin D receptor Taq I polymorphism and the risk of prostate cancer: a meta-analysis

Numerous previous studies reported the association of Vitamin D receptor gene Taq Ipolymorphism with prostate cancer risk, however these results were controversial. In order to provide a relatively comprehensive description of this relationship, we conducted this meta-analysis by searching PubMed, Embase, and China National Knowledge Infrastructure. Finally, 36 studies with 8,423 cases and 8,887 controls were included. Taq I polymorphism was found to marginally increase the prostate cancer risk in recessive genetic model (tt/Tt vs. TT: Odds Ratio (OR) = 0.89, 95% Confidence Interval (CI) = 0.80–1.00, p = 0.05) and allele genetic model (t vs. T allele: OR = 0.91, 95% CI = 0.84–0.99, p = 0.003) in the overall analysis. Subgroup analyses showed that significant increased risk was found in Asians in homozygote model (tt vs. TT: OR = 0.63, 95% CI = 0.41–0.95, p = 0.029) and allele genetic model (t vs. T: OR = 0.78, 95% CI = 0.67–0.90, p = 0.002), and in the subgroup of population-based controls in all the genetic models. These results suggest that Taq Ipolymorphism might be a risk factor of prostate cancer risk, especially in Asians. It could be considered as a promising target to predict the prostate cancer risk for clinical practice.

Vitamin D Receptor Signaling and Cancer

The vitamin D receptor (VDR) binds the secosteroid hormone 1,25(OH)₂D₃ with high affinity and regulates gene programs that control a serum calcium levels, as well as cell proliferation and differentiation. A significant focus has been to exploit the VDR in cancer settings. Although preclinical studies have been strongly encouraging, to date clinical trials have delivered equivocal findings that have paused the clinical translation of these compounds. However, it is entirely possible that mining of genomic data will help to refine precisely what are the key anticancer actions of vitamin D compounds and where these can be used most effectively.

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.

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.

Updated analysis of vitamin D receptor gene FokI polymorphism and prostate cancer susceptibility

INTRODUCTION

Polymorphisms of the vitamin D receptor (VDR) gene have been investigated in various case-control studies to evaluate prostate cancer susceptibility; however, published data on the association between vitamin D receptor gene FokI polymorphism and prostate cancer risk are inconclusive.

MATERIAL AND METHODS

To assess the impact of vitamin D receptor gene FokI polymorphism, we performed a meta-analysis of eligible studies including 9,720 patients and 9,710 control subjects.

RESULTS

The overall results indicated no obvious association of this variant on prostate cancer risk. However, in subgroup analysis by ethnicity, positive associations existed in Caucasian descendents for allelic contrast (OR = 1.03, 95% CI: 1.00-1.06, p_{heterogeneity} = 0.552, p = 0.026) and the dominant genetic model (OR = 1.03, 95% CI: 1.00-1.05, p_{heterogeneity} = 0.856, p = 0.032). In the subgroup analysis by tumor stage, there was a significant association between this variant and advanced prostate cancer under the recessive genetic model (OR = 1.15, 95% CI: 1.01-1.32, p_{heterogeneity} = 0.469, p = 0.032). In the subgroup analysis by source of control, association of the VDR FokI polymorphism and prostate cancer susceptibility was also found in population-based studies under homozygote comparison and the recessive genetic model.

CONCLUSIONS

The VDR FokI polymorphism may contribute to the risk of developing prostate cancer in Caucasian and population-based studies. Further large, well-designed studies are warranted to confirm this conclusion in more detail.

Association of vitamin D levels and risk of ovarian cancer: a Mendelian randomization study

BACKGROUND

In vitro and observational epidemiological studies suggest that vitamin D may play a role in cancer prevention. However, the relationship between vitamin D and ovarian cancer is uncertain, with observational studies generating conflicting findings. A potential limitation of observational studies is inadequate control of confounding. To overcome this problem, we used Mendelian randomization (MR) to evaluate the association between single nucleotide polymorphisms (SNPs) associated with circulating 25-hydroxyvitamin D [25(OH)D] concentration and risk of ovarian cancer.

METHODS

We employed SNPs with well-established associations with 25(OH)D concentration as instrumental variables for MR: rs7944926 (DHCR7), rs12794714 (CYP2R1) and rs2282679 (GC). We included 31 719 women of European ancestry (10 065 cases, 21 654 controls) from the Ovarian Cancer Association Consortium, who were genotyped using customized Illumina Infinium iSelect (iCOGS) arrays. A two-sample (summary data) MR approach was used and analyses were performed separately for all ovarian cancer (10 065 cases) and for high-grade serous ovarian cancer (4121 cases).

RESULTS

The odds ratio for epithelial ovarian cancer risk (10 065 cases) estimated by combining the individual SNP associations using inverse variance weighting was 1.27 (95% confidence interval: 1.06 to 1.51) per 20 nmol/L decrease in 25(OH)D concentration. The estimated odds ratio for high-grade serous epithelial ovarian cancer (4121 cases) was 1.54 (1.19, 2.01).

CONCLUSIONS

Genetically lowered 25-hydroxyvitamin D concentrations were associated with higher ovarian cancer susceptibility in Europeans. These findings suggest that increasing plasma vitamin D levels may reduce risk of ovarian cancer.

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.

Markers of Vitamin D Exposure and Esophageal Cancer Risk: A Systematic Review and Meta-analysis

Vitamin D has been associated with reduced risk of many cancers, but evidence for esophageal cancer is mixed. To clarify the role of vitamin D, we performed a systematic review and meta-analysis to evaluate the association of vitamin D exposures and esophageal neoplasia, including adenocarcinoma, squamous cell carcinoma (SCC), Barrett's esophagus, and squamous dysplasia. Ovid MEDLINE, EMBASE, and Web of Science were searched from inception to September 2015. Fifteen publications in relation to circulating 25-hydroxyvitamin D [25(OH)D; n = 3], vitamin D intake (n = 4), UVB exposure (n = 1), and genetic factors (n = 7) were retrieved. Higher [25(OH)D] was associated with increased risk of cancer [adenocarcinoma or SCC, OR = 1.39; 95% confidence interval (CI), 1.04-1.74], with the majority of participants coming from China. No association was observed between vitamin D intake and risk of cancer overall (OR, 1.03; 0.65-1.42); however, a nonsignificantly increased risk for adenocarcinoma (OR, 1.45; 0.65-2.24) and nonsignificantly decreased risk for SCC (OR, 0.80; 0.48-1.12) were observed. One study reported a decreased risk of adenocarcinoma with higher UVB exposure. A decreased risk was found for VDR haplotype rs2238135(G)/rs1989969(T) carriers (OR, 0.45; 0.00-0.91), and a suggestive association was observed for rs2107301. In conclusion, no consistent associations were observed between vitamin D exposures and occurrence of esophageal lesions. Further adequately powered, well-designed studies are needed before conclusions can be made. Cancer Epidemiol Biomarkers Prev; 25(6); 877-86. ©2016 AACR.

Polymorphisms of vitamin D receptor gene TaqI susceptibility of prostate cancer: a meta-analysis

Objective

Many studies have investigated the association of the vitamin D receptor gene TaqI polymorphism with prostate cancer (PCa) risk. However, the evidence is inadequate to draw robust conclusions. To shed light on these inconclusive findings, we conducted a meta-analysis.

Materials and methods

We searched PubMed for eligible articles. The relevant data were abstracted by two independent reviewers with the Stata 11.0 software.

Results

A total of 27 studies were included. The pooled outcomes indicated that the TaqI genetic polymorphisms were significantly associated with the risk of PCa (T vs t allele: odds ratio [OR] =1.11, 95% confidence interval [CI] =1.03–1.21, P=0.008; TT vs tt: OR =1.19, 95% CI =1.01–1.42, P=0.040; TT + Tt vs tt: OR =1.18, 95% CI =1.02–1.38, P=0.031), especially in the Asian population (T vs t allele: OR =1.11, 95% CI =1.03–1.21, P=0.008; TT/Tt vs tt: OR =1.93, 95% CI =1.02–3.66, P=0.043). In the tumor stage stratified analyses, the pooled results showed no significant difference in genetic polymorphisms between the local tumor group and the control group or between the local tumor group and the advanced tumor group. However, the genotypes TT and TT/Tt were significantly higher in the advanced PCa group compared to the control group (T vs t allele: OR =1.20, 95% CI =1.01–1.42, P=0.040; TT vs tt: OR =1.34, 95% CI =1.08–1.67, P=0.009; TT/Tt vs tt: OR =1.28, 95% CI =1.05–1.56, P=0.015).

Conclusion

The vitamin D receptor gene TaqI allele polymorphism might be associated with a PCa risk, especially in Asians, which might provide new clues for the pathogenesis research and clinical diagnosis of PCa in the future.

Circulating vitamin D, vitamin D-related genetic variation, and risk of fatal prostate cancer in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium

BACKGROUND

Evidence from experimental animal and cell line studies supports a beneficial role for vitamin D in prostate cancer (PCa). Although the results from human studies have been mainly null for overall PCa risk, there may be a benefit for survival. This study assessed the associations of circulating 25-hydroxyvitamin D (25(OH)D) and common variations in key vitamin D-related genes with fatal PCa.

METHODS

In a large cohort consortium, 518 fatal cases and 2986 controls with 25(OH)D data were identified. Genotyping information for 91 single-nucleotide polymorphisms (SNPs) in 7 vitamin D-related genes (vitamin D receptor, group-specific component, cytochrome P450 27A1 [CYP27A1], CYP27B1, CYP24A1, CYP2R1, and retinoid X receptor α) was available for 496 fatal cases and 3577 controls. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of 25(OH)D and SNPs with fatal PCa. The study also tested for 25(OH)D-SNP interactions among 264 fatal cases and 1169 controls.

RESULTS

No statistically significant relationship was observed between 25(OH)D and fatal PCa (OR for extreme quartiles, 0.86; 95% CI, 0.65-1.14; P for trend = .22) or the main effects of the SNPs and fatal PCa. There was evidence suggesting that associations of several SNPs, including 5 related to circulating 25(OH)D, with fatal PCa were modified by 25(OH)D. Individually, these associations did not remain significant after multiple testing; however, the P value for the set-based test for CYP2R1 was .002.

CONCLUSIONS

Statistically significant associations were not observed for either 25(OH)D or vitamin D-related SNPs with fatal PCa. The effect modification of 25(OH)D associations by biologically plausible genetic variation may deserve further exploration.

Association of the CYP24A1-rs2296241 polymorphism of the vitamin D catabolism enzyme with hormone-related cancer risk: a meta-analysis

BACKGROUND

The evidence for vitamin D reducing cancer risk is inconsistent, and it is not clear whether this reduction is related to variation in cytochrome P450 (CYP)24A1, the only enzyme known to degrade active vitamin D. We focused on evaluating the association of CYP24A1-rs2296241 polymorphism with hormone-related cancer risk by conducting a meta-analysis.

METHODS

A systematic literature search was conducted in April 2014 (updated in December 2014) to identify eligible studies. A random-effects model was used to pool the odds ratio (OR).

RESULTS

Eleven studies including 5,145 cases and 5,136 controls were considered for the allelic model, and eight studies of 3,959 cases and 3,560 controls were utilized for the additive, recessive, and dominant models. There was no significant association between CYP24A1-rs2296241 and hormone-related cancer risk in any of the models, yet substantial heterogeneity was observed. Subgroup analyses indicated that CYP24A1-rs2296241 variation reduced the prostate cancer risk in the additive (OR 0.91, 95% confidence interval 0.85-0.97) and recessive (OR 0.80, 95% confidence interval 0.67-0.95) models, with no evidence of heterogeneity.

CONCLUSION

This meta-analysis indicated that CYP24A1-rs2296241 polymorphism reduced the androgen-related prostate cancer risk in additive and recessive models. More genetic loci are needed to confirm the effect of CYP24A1 variation on the risk of prostate cancer.

Common genetic variants related to vitamin D status are not associated with esophageal squamous cell carcinoma risk in China

BACKGROUND

Few studies have examined the association of common genetic variants related to vitamin D metabolism and signaling to esophageal squamous cell carcinoma (ESCC).

METHODS

We evaluated the association between 12 single nucleotide polymorphisms (SNPs) in four genes related to vitamin D levels and ESCC risk using data from a genome-wide association study. Participants were recruited from the Shanxi Upper Gastrointestinal Cancer Genetics Project and the Linxian Nutrition Intervention Trials, and included 1942 ESCC cases and 2111 controls. We used logistic models to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the SNP associations, after controlling for age and gender.

RESULTS

None of the 12 evaluated SNPs in the four vitamin D-related genes were significantly associated with risk of ESCC. The strongest associations were for rs3794060 (P=0.07) and rs12800438 (P=0.08) in the DHCR7/NADSYN1 gene. No association between vitamin D-related SNPs and risk of ESCC was observed in a genotype score analysis that included all 12 SNPs. ORs for quartiles 2, 3 and 4 of the genotype scores were 0.83 (95% CI: 0.68, 1.01), 1.02 (0.85, 1.21), and 1.08 (0.89, 1.30), respectively, with no evidence for a significant monotonic trend (P=0.120).

CONCLUSIONS

Our results suggested that common genetic variants related to vitamin D levels are not associated with risk of ESCC in this Chinese population.

Oral vitamin D increases the frequencies of CD38+ human B cells and ameliorates IL-17-producing T cells

Vitamin D deficiency (serum 25-hydroxyvitamin D < 50 nm) has been associated with the onset of immunological diseases including atopic dermatitis (AD), cutaneous or systemic lupus erythematosus and allergic asthma. In this study, we assessed whether oral vitamin D (cholecalciferol) supplementation leads to a systemic modulation of the phenotype of circulating lymphocyte populations and whether a defined serum 25-hydroxyvitamin D (25(OH)D) concentration can be related to the effects on lymphocytes. Cholecalciferol was administered in a dose-escalation setting to vitamin D-deficient individuals from 2000 up to 8000 IU daily for 12 weeks. Individuals without cholecalciferol intake served as controls. Peripheral B cells and T cells were examined by multicolour flow cytometric analysis. The mean serum 25(OH)D concentrations increased upon cholecalciferol intake up to 159 ± 28.7 nm, and remained low in the control group 30.0 ± 12.5 nm. Following cholecalciferol intake, the frequencies of circulating CD38 expressing B cells were significantly increased and IFN-γ+ , and/or IL-17+ CD4+ T helper cells were decreased. These data were identified to correlate with the serum 25(OH)D levels by applying two different analysis approaches (ROC and a nonlinear regression analysis). Our data indicate that increasing 25(OH)D serum concentrations are associated with an increased expression of CD38 on B cells and a decreased T-cell-dependent proinflammatory cytokine production. The therapeutical role of our findings in systemic immunological diseases should be explored in the future by further controlled clinical studies.

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

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

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

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

The role of vitamin D in reducing cancer risk and progression

Vitamin D is not really a vitamin but the precursor to the potent steroid hormone calcitriol, which has widespread actions throughout the body. Calcitriol regulates numerous cellular pathways that could have a role in determining cancer risk and prognosis. Although epidemiological and early clinical trials are inconsistent, and randomized control trials in humans do not yet exist to conclusively support a beneficial role for vitamin D, accumulating results from preclinical and some clinical studies strongly suggest that vitamin D deficiency increases the risk of developing cancer and that avoiding deficiency and adding vitamin D supplements might be an economical and safe way to reduce cancer incidence and improve cancer prognosis and outcome.

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

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

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

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

Cell-type specific features of circular RNA expression

Thousands of loci in the human and mouse genomes give rise to circular RNA transcripts; at many of these loci, the predominant RNA isoform is a circle. Using an improved computational approach for circular RNA identification, we found widespread circular RNA expression in Drosophila melanogaster and estimate that in humans, circular RNA may account for 1% as many molecules as poly(A) RNA. Analysis of data from the ENCODE consortium revealed that the repertoire of genes expressing circular RNA, the ratio of circular to linear transcripts for each gene, and even the pattern of splice isoforms of circular RNAs from each gene were cell-type specific. These results suggest that biogenesis of circular RNA is an integral, conserved, and regulated feature of the gene expression program.

Genetic variation in the vitamin d pathway in relation to risk of prostate cancer--results from the breast and prostate cancer cohort consortium

BACKGROUND

Studies suggest that vitamin D status may be associated with prostate cancer risk although the direction and strength of this association differs between experimental and observational studies. Genome-wide association studies have identified genetic variants associated with 25-hydroxyvitamin D [25(OH)D] status. We examined prostate cancer risk in relation to single-nucleotide polymorphisms (SNP) in four genes shown to predict circulating levels of 25(OH)D.

METHODS

SNP markers localized to each of four genes (GC, CYP24A1, CYP2R1, and DHCR7) previously associated with 25(OH)D were genotyped in 10,018 cases and 11,052 controls from the National Cancer Institute (NCI) Breast and Prostate Cancer Cohort Consortium. Logistic regression was used to estimate the individual and cumulative association between genetic variants and risk of overall and aggressive prostate cancer.

RESULTS

We observed a decreased risk of aggressive prostate cancer among men with the allele in rs6013897 near CYP24A1 associated with lower serum 25(OH)D [per A allele, OR, 0.86; 95% confidence interval (CI), 0.80-0.93; Ptrend = 0.0002) but an increased risk for nonaggressive disease (per A allele: OR, 1.10; 95% CI, 1.04-1.17; Ptrend = 0.002). Examination of a polygenic score of the four SNPs revealed statistically significantly lower risk of aggressive prostate cancer among men with a greater number of low vitamin D alleles (OR for 6-8 vs. 0-1 alleles, 0.66; 95% CI, 0.44-0.98; Ptrend = 0.003).

CONCLUSIONS

In this large, pooled analysis, genetic variants related to lower 25(OH)D levels were associated with a decreased risk of aggressive prostate cancer.

IMPACT

Our genetic findings do not support a protective association between loci known to influence vitamin D levels and prostate cancer risk.

Vitamin d receptor gene variants and esophageal adenocarcinoma risk: a population-based case-control study

PURPOSE

Polymorphisms in the vitamin D receptor (VDR) gene may be of etiological importance in determining cancer risk. The aim of this study was to assess the association between common VDR gene polymorphisms and esophageal adenocarcinoma (EAC) risk in an all-Ireland population-based case-control study.

METHODS

EAC cases and frequency-matched controls by age and gender recruited between March 2002 and December 2004 throughout Ireland were included. Participants were interviewed, and a blood sample collected for DNA extraction. Twenty-seven single nucleotide polymorphisms in the VDR gene were genotyped using Sequenom or TaqMan assays while the poly(A) microsatellite was genotyped by fluorescent fragment analysis. Unconditional logistic regression was applied to assess the association between VDR polymorphisms and EAC risk.

RESULTS

A total of 224 cases of EAC and 256 controls were involved in analyses. After adjustment for potential confounders, TT homozygotes at rs2238139 and rs2107301 had significantly reduced risks of EAC compared with CC homozygotes. In contrast, SS alleles of the poly(A) microsatellite had significantly elevated risks of EAC compared with SL/LL alleles. However, following permutation analyses to adjust for multiple comparisons, no significant associations were observed between any VDR gene polymorphism and EAC risk.

CONCLUSIONS

VDR gene polymorphisms were not significantly associated with EAC development in this Irish population. Confirmation is required from larger studies.