Association of vitamin-D receptor (Fok-I) gene polymorphism with bladder cancer in an Indian population

Association of TaqI (rs731236) Polymorphism of Vitamin D Receptor Gene with Lumbar Degenerative Disc Disease

BACKGROUND

Lumbar degenerative disc disease (LDDD) significantly contributes to low back pain, with a complicated etiology involving genetic and environmental facts. The aim of study was to investigate the association between the TaqI (rs731236) polymorphism of the vitamin D receptor (VDR) gene with LDDD.

METHODS

In total, 248 patients with symptomatic LDDD and 146 control subjects were examined. The evaluation of clinical features of patients with LDDD comprised radiodiagnostic magnetic resonance imaging, neurologic examinations, pain scores including the visual analog scale (VAS), and disability investigation with Oswestry Disability Index (ODI). Genotyping of the VDR gene polymorphism was conducted using polymerase chain reaction-based methods.

RESULTS

Individuals of the LDDD group who were VDR TaqI AA genotype carriers were significantly greater than the other group (P = 0.014), whereas those with GG genotype were significantly lower (P = 0.028) in the patient group. In addition, VAS and ODI scores were significantly lower in the GG genotype carrier group, whereas AA genotype carriers had the greatest scores (P = 0.004). Carrying the G allele decreased the risk of LDDD 1.7 times (P = 0.014) and carrying the A allele enhanced the risk 1.8 times (P = 0.028). Moreover, G-allele carriers had significantly lower VAS (P = 0.002) and ODI scores (P < 0.0001).

CONCLUSIONS

VDR TaqI (rs731236) GG genotype and G allele have protective potential, whereas the AA genotype and A allele are risk factors for LDDD. The findings reveal a statistically significant association of the TaqI (rs731236) polymorphism of VDR gene polymorphism with LDDD. This result highlights the potential role of genetic factors in developing LDDD and suggests avenues for future research in genetic screening and personalized treatment strategies.

Genetic Polymorphisms Involved in Bladder Cancer: A Global Review

Bladder cancer (BC) has been associated with genetic susceptibility. Single peptide polymorphisms (SNPs) can modulate BC susceptibility. A literature search was performed covering the period between January 2000 and October 2020. Overall, 334 articles were selected, reporting 455 SNPs located in 244 genes. The selected 455 SNPs were further investigated. All SNPs that were associated with smoking and environmental exposure were excluded from this study. A total of 197 genes and 343 SNPs were found to be associated with BC, among which 177 genes and 291 SNPs had congruent results across all available studies. These genes and SNPs were classified into eight different categories according to their function.

Vitamin D and Gastric Cancer: A Ray of Sunshine?

Gastric cancer (GC) is one of the most aggressive malignancies, currently ranking third among cancers leading to death worldwide. Despite the recent advancements in GC research, it is most often diagnosed during the terminal stages and with limited treatment modalities contributing to its poor prognosis and a lower survival rate.

Much research has provided conflicting results between a vitamin D deficient status and the development of GC. Vitamin D is a well-known and essential hormone classically known to regulate calcium and phosphate absorption, enabling adequate mineralization of the skeletal system. However, the function of vitamin D is multidimensional. It possesses unique roles, including acting as antioxidants or immunomodulators while crossing the cell membrane, performing several intracellular functions, participating in gene regulation, and controlling the proliferation and invasion of cancer cells, including those of GC.

In light of this, it is imperative to analyze the causes of GC, review the factors that can be used to enhance the effectiveness of treatments, and discover the tools to determine prognosis, reduce mortality, and prevent GC development. In this review, we have summarized recent investigations on multiple associations between vitamin D and GC, emphasizing genetic associations, vitamin D receptors, and the prevalence of hormone deficiency in those developing this aggressive malignancy.

Association between common variants in vitamin D receptor gene and susceptibility to Non-Hodgkin's lymphoma: a case-control study

Vitamin D (VDR)-mediated signaling contributes to the cell signaling pathways that affect cancer development. This study is conducted on 104 patients diagnosed with non-Hodgkin's lymphoma (NHL) and 246 healthy subjects to investigate the link between five genetic variants spanning the VDR gene and the risk of this malignancy in Iranian subjects. The PCR-RFLP method was used for the analysis of BsmI (rs1544410), ApaI (rs7975232), FokI (rs2228570) and TaqI (rs731236) variants. A simple Tetra-ARMS-PCR technique was employed for the genotyping of the Cdx2 (rs11568820) variant. No significant link was found between both groups regarding ApaI (rs7975232) and FokI (rs2228570) variants (P > 0.05). Also, different genetic models of TaqI (rs731236), BsmI (rs1544410) and Cdx2 (rs11568820) polymorphisms were significantly correlated to decreased risk of NHL (Odd ratios <1). We found three haplotypes were strongly associated with an increased risk of NHL (P < 0.0001). Linkage-disequilibrium (LD) analysis showed a strong linkage between TaqI (rs731236) and BsmI (rs1544410) among NHL case and control subjects. Our findings indicated that functional variants of the VDR gene are linked to a decreased risk of NHL in our population. Further replication studies in different ethnic groups are needed to validate our results.

Association of Vitamin D Receptor Polymorphisms (FokI (Rs2228570), ApaI (Rs7975232), BsmI (Rs1544410), and TaqI (Rs731236)) with Gastric Cancer in a Kurdish Population from West of Iran

Background

The association of 1,25-dihydroxy vitamin D3 (1,25(OH)2D3) and its receptor, vitamin D receptor (VDR), with cancer types have been studied. However, there are controversial findings regarding the association of specific VDR polymorphisms with different kinds of cancers. In the current study, we investigated the association of VDR polymorphisms (Fok1 (rs2228570), ApaI (rs7975232), BsmI (rs1544410), and TaqI (rs731236)) with the risk of gastric cancer in a Kurdish population of Kermanshah in Iran for the first time.

Methods

In this case-control study, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used in 99 gastric cancer patients and 100 healthy subjects as controls.

Results

The frequencies of f (FokI), b (BsmI), t (TaqI), and a (ApaI) alleles were: 55.6%, 27.3%, 62.1%, and 44.95% in the patient group, respectively and 42%, 29.5%, 54.5%, and 46.0% in the control group, respectively. Analysis of the results indicated that there was a positive association between the frequency of FokI genotypes with gastric cancer risk (p= 0.021). However, no statistically significant association of BsmI, Taq1, and ApaI polymorphisms of VDR was detected in gastric patients when compared with healthy individuals.

Conclusion

VDR-FokI polymorphism could increase the risk of GC development and predispose to the disease by mechanisms.

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.

The Role of Steroid Hormone Receptors in Urothelial Tumorigenesis

Preclinical and/or clinical evidence has indicated a potential role of steroid hormone-mediated signaling pathways in the development of various neoplastic diseases, while precise mechanisms for the functions of specific receptors remain poorly understood. Specifically, in urothelial cancer where sex-related differences particularly in its incidence are noted, activation of sex hormone receptors, such as androgen receptor and estrogen receptor-β, has been associated with the induction of tumor development. More recently, glucocorticoid receptor has been implied to function as a suppressor of urothelial tumorigenesis. This article summarizes and discusses available data suggesting that steroid hormone receptors, including androgen receptor, estrogen receptor-α, estrogen receptor-β, glucocorticoid receptor, progesterone receptor and vitamin D receptor, as well as their related signals, contribute to modulating urothelial tumorigenesis.

Genetic variation in the maternal vitamin D receptor FokI gene as a risk factor for recurrent pregnancy loss

PURPOSE

Recurrent pregnancy loss (RPL) is a reproductive disorder defined as the loss of two or more pregnancies before 24 weeks of gestation. Despite the fact that several mechanisms have been previously described for the pathogenesis of RPL, the causes of ∼50% of cases remain unknown. However, recent studies indicate association of vitamin D deficiency with adverse pregnancy outcome, including RPL. The vitamin D receptor (VDR) is a crucial mediator of the pleiotropic cellular effects of vitamin D. Its function is influenced by several single nucleotide polymorphisms (SNPs). The main objective of this study is to assess whether maternal VDR SNPs are associated with the risk of RPL in Slovenian and Croatian women.

METHODS

A case-control study including 320 women with RPL and control women is designed to examine the potential association of VDR polymorphisms (FokI rs222857, Cdx2 rs11568820, and Taq1 rs731236) with RPL. Genotyping is performed using polymerase chain reaction and restriction fragment length polymorphism methods.

RESULTS

We find a statistically significant higher frequency of the rs222857 CC genotype (χ² = 6.61, p = .036) and C allele (χ² = 5.93, p = .015) in RPL women compared to controls. Subsequently, the odds for RPL for the rs222857 are increased under the recessive (CCvsCT + TT: OR = 1.78; 95% CI = 1.12-2.82; p = .015) and the codominant (CCvsTT: OR = 2.21; 95% CI = 1.08-4.53; p = .029; CCvsCT: OR = 1.68; 95% CI = 1.04-2.72; p = .036) genetic models. The other two analyzed polymorphisms did not show any statistical significant result.

CONCLUSIONS

Our results suggest that variations in the maternal VDR FokI gene might be associated with RPL in Slovenian and Croatian women.

Low serum 25-hydroxyvitamin D is associated with increased bladder cancer risk: A systematic review and evidence of a potential mechanism

The development of some cancers is associated with vitamin D deficiency. We suggest that reduced conversion of 25-hydroxyvitamin D (25(OH)D) to 1,25-dihydroxyvitamin D (1,25(OH)₂D) and the resulting modification of tissue specific immune responses may be key. Non-muscle-invasive bladder cancer is highly immunoresponsive and stimulation of an inflammatory response by intravesical bacillus Calmette-Guerin (BCG) treatment prevents recurrence. To assess the relationship between serum 25(OH)D and bladder cancer risk we conducted a systematic review. To test our hypothesis, the synthesis of 1,25(OH)₂D by human bladder epithelial cell lines (T24/83 and RT4) was examined. Studies were identified from Medline, Web of Science, Embase and Cochrane library (limited to English language, humans and 1990-2018). After removal of duplicates, title and abstract review 6 full papers were appraised. Low vitamin D levels were associated with bladder cancer risk in 5/6 of the studies. Both cell lines express the vitamin D receptor, 25-hydroxyvitamin D 1α-hydroxylase (1α-OHase) and 24-hydroxylase (24-OHase) mRNA, which was induced by 1,25(OH)₂D. 24-OHase mRNA was also increased by 25(OH)D indicating 1α-OHase activity. Both cell types expressed TLR1,2,4 and the TLR partners MyD88 and CD14mRNA. Cathelicidin mRNA was undetectable in both cell lines but was induced by 1,25(OH)₂D and 25(OH)D in RT4 cells. The systematic review demonstrated that bladder cancer risk correlates with serum 25(OH)D levels. In addition, we have shown that transitional epithelial cells express functional vitamin D signaling and can synthesize sufficient 1,25(OH)₂D to stimulate a local immune response. We suggest that in order to maintain optimal immune surveillance within the bladder adequate levels of serum 25(OH)D are required for direct synthesis of 1,25(OH)₂D by bladder epithelial cells.

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.

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 and urological cancers

Introduction

Vitamin D controls calcium and phosphate homeostasis. Additionally, it has been proven that vitamin D is an important modulator of cellular differentiation and proliferation in a number of normal and malignant cells. Vitamin D can regulate proliferation, apoptosis, and cell adhesion at the tumor cell level. It also modifies tumor angiogenesis, invasion, and metastasis and also decreases oxidative DNA damage.

Material and methods

The Medline and Web of Science databases were searched without time limit on October 2015 using the terms ‘vitamin D’ in conjunction with ‘kidney cancer’, ‘bladder cancer’, ‘prostate cancer’, and ‘testis cancer’. Autoalerts in Medline were also run and reference lists of original articles, review articles, and book chapters were searched for further eligible articles.

Results

In recent years, vitamin D has received vast attention due to suggestions that it may have a crucial role in the prevention and therapy of various cancers. Many epidemiologic studies have reported the impact of VD3 on preventing several cancers and other pathologies. Assuming that vitamin D status changes cancer risk, enough vitamin D supply would be an easy, economical, and safe cancer incidence and mortality reduction method. However, despite numerous researches, the role of vitamin D in cancer incidence and therapy remains unclear.

Conclusions

The impact of vitamin D is well described in breast, colon, and prostate cancer; yet, there is only little published about other malignancies.

Comparative efficacy of vitamin D status in reducing the risk of bladder cancer: A systematic review and network meta-analysis

OBJECTIVES

The optimal concentration of individual vitamin D intake for preventing bladder cancer has not, to our knowledge, been defined. To evaluate the comparative efficacy of different serum 25-hydroxyvitamin D concentrations in preventing bladder cancer, we conducted a systematic search of the literature published up to April 2015.

METHODS

We applied a pairwise meta-analysis to estimate direct evidence from intervention-control studies and a network meta-analysis within a Bayesian framework to combine direct and indirect evidence. Moreover, a dose-response curve was utilized to predict the optimal median serum 25-hydroxyvitamin D concentration based on the odds ratio (OR) for each quintile concentration.

METHODS

Seven studies of a total of 90757 participants, including 2509 bladder cancer patients, were included. Two prospective cohort studies with 57 591 participants and 494 bladder cancer patients, and five case-control studies with 33 166 participants and 2264 bladder cancer patients. From the network meta-analysis, we observed that sufficient serum 25-hydroxyvitamin D concentrations (>75 nmol/L) were superior to all other 25-hydroxyvitamin D concentrations in decreasing the risk of bladder cancer: OR = 0.68 and 95% credible interval (CrI) 0.52 to 0.87 compared with severely deficient concentrations (<25 nmol/L); OR = 0.65 and 95% CrI 0.49 to 0.86 compared with moderately deficient concentrations (25-37.5 nmol/L); OR = 0.61 and 95% CrI 0.47 to 0.80 compared with slightly deficient concentrations (37.5-50 nmol/L); and OR = 0.65 and 95% CrI 0.48 to 0.85 compared with insufficient concentrations (50-75 nmol/L). In addition, we noted a roughly inverse correlation between bladder cancer risk and 25-hydroxyvitamin D concentrations (R(2) = 0.98, P = 0.007).

CONCLUSIONS

Ensuring sufficient serum 25-hydroxyvitamin D concentrations might play an important role in decreasing the risk of bladder cancer. The serum 25-hydroxyvitamin D concentration ≥74 nmol/L was associated with a 60% lower risk of bladder cancer incidence.

Steroid Hormone Receptor Signals as Prognosticators for Urothelial Tumor

There is a substantial amount of preclinical or clinical evidence suggesting that steroid hormone receptor-mediated signals play a critical role in urothelial tumorigenesis and tumor progression. These receptors include androgen receptor, estrogen receptors, glucocorticoid receptor, progesterone receptor, vitamin D receptor, retinoid receptors, peroxisome proliferator-activated receptors, and others including orphan receptors. In particular, studies using urothelial cancer tissue specimens have demonstrated that elevated or reduced expression of these receptors as well as alterations of their upstream or downstream pathways correlates with patient outcomes. This review summarizes and discusses available data suggesting that steroid hormone receptors and related signals serve as biomarkers for urothelial carcinoma and are able to predict tumor recurrence or progression.

Association of FokI polymorphism of vitamin D receptor with urothelial bladder cancer in Tunisians: role of tobacco smoking and plasma vitamin D concentration

The aim of the study was to test whether the VDR FokI polymorphism is associated with the risk of urothelial bladder cancer (UBC) in Tunisians. The study included 200 unrelated patients with UBC and 200 healthy controls. Genotyping of the VDR FokI polymorphism was determined by PCR-RFLP method. Plasma 25-hydroxyvitamin D concentrations were measured by immunoassay. Binary logistic regression model was applied to test how the association of VDR FokI polymorphism is independent of potential confounding factors. Genotype distribution (FF, 45 vs. 55 %; Ff, 52.1 vs. 47.9 %, and ff, 12 vs. 5.5 %, respectively) and allele frequencies (F, 66.5 vs. 74.8 % and f, 33.5 vs. 25.2 %, respectively) were significantly different between UBC patients and controls. The "ff" genotype [OR (95 % CI), 2.66 (1.24-5.73); p = 0.012] and "f" allele [1.49 (1.09-2.02); p = 0.010] were associated with increased risk of UBC. The association remained significant in multivariate analysis. Stratified analyses showed that VDR FokI polymorphism is only associated with UBC risk in ever-smokers, subjects exposed to chemical carcinogens and those with plasma 25-hydroxyvitamin D over 12 μg/L. The "f" allele of VDR FokI polymorphism is associated with a higher risk of UBC in Tunisians, especially in smokers as well as subjects with occupational exposition and subjects without vitamin D deficiency. These results should be replicated in other ethnic groups and the influence of other genetic factors and environments on this association should be investigated.

Prospective associations between vitamin D status, vitamin D-related gene polymorphisms, and risk of tobacco-related cancers

BACKGROUND

Experimental evidence has suggested that vitamin D may be protective against tobacco-related cancers through the inhibition of the formation of tumors induced by tobacco carcinogens. To our knowledge, only one previous epidemiologic study investigated the association between vitamin D status and tobacco-related cancer risk, and no study has focused on vitamin D-related gene polymorphisms.

OBJECTIVE

Our objective was to prospectively study the association between plasma 25-hydroxyvitamin D [25(OH)D] concentrations, vitamin D-related gene polymorphisms, and risk of tobacco-related cancers.

DESIGN

A total of 209 tobacco-related cancers were diagnosed within the SU.VI.MAX (Supplémentation en vitamines et minéraux antioxydants) cohort (1994-2007) and were matched with 418 controls as part of a nested case-control study. Tobacco-related cancers (i.e., cancers for which tobacco is one of the risk factors) included several sites in the respiratory, digestive, reproductive, and urinary systems. Total plasma 25(OH)D was assessed with the use of an electrochemoluminescent assay. Polymorphisms were determined with the use of a TaqMan assay. Conditional logistic regression models were computed.

RESULTS

A 25(OH)D concentration ≥30 ng/mL was associated with reduced risk of tobacco-related cancers (OR for ≥30 compared with <30 ng/mL: 0.59; 95% CI 0.35, 0.99; P = 0.046). This association was observed in former and current smokers (OR for ≥30 compared with <30 ng/mL: 0.43; 95% CI: 0.23, 0.84; P = 0.01) but not in never smokers (P = 0.8). The vitamin D receptor (VDR) FokI AA genotype and retinoid X receptor (RXR) rs7861779 TT genotype were associated with increased risk of tobacco-related cancers [OR for homozygous mutant type (MT) compared with wild type (WT): 1.87; 95% CI: 1.08, 3.23; P-trend = 0.02; OR for heterozygous type (HT) plus MT compared with WT: 1.60; 95% CI: 1.07, 2.38; P = 0.02].

CONCLUSIONS

In this prospective study, high vitamin D status [25(OH)D concentration ≥30 ng/mL] was associated with decreased risk of tobacco-related cancers, especially in smokers. These results, which are supported by mechanistic plausibility, suggest that vitamin D may contribute to the prevention of tobacco-induced cancers in smokers and deserve additional investigation. The SU.VI.MAX trial was registered at clinicaltrials.gov as NCT00272428.

Expression of Vitamin D Receptor (VDR) Positively Correlates with Survival of Urothelial Bladder Cancer Patients

Vitamin D3 shows tumoristatic and anticancer effects by acting through the vitamin D receptor (VDR), while hydroxylation of 25-hydroxyvitamin D3 at position 1α by CYP27B1 is an essential step in its activation. The expression of both the VDR and CYP27B1 has been found in many normal and cancer tissues, but there is a lack of information about its expression in human bladder cancers. The aim of the present research was to examine whether the expression of the VDR and CYP27B1 in bladder cancer was related to the prognostic markers and disease outcome. We analyzed VDR and CYP27B1 in samples of tumor and normal tissues obtained from 71 urinary bladder cancer patients. The highest VDR immunostaining was found in normal epithelium and was significantly lower in bladder cancer cells (p < 0.001 with Mann–Whitney U test). VDR expression was lowest in more advanced (pT2b–pT4) (p = 0.005 with Mann–Whitney U test) and metastasizing cancers (p < 0.05 and p = 0.004 with Mann–Whitney U test for nuclear and cytoplasmic VDR immunostaining, respectively). The lack of cytoplasmic and nuclear VDR was also related to shorter overall survival (for cytoplasmic VDR immunolocalization 13.3 vs. 55.3 months of survival, HR = 1.92, p = 0.04 and for nuclear VDR immunostaining 13.5 vs. 55.3 months of survival, HR = 2.47, p = 0.002 with Mantel-Cox test). In cases with the lack of high cytoplasmic VDR staining the non-classic differentiations (NDs) was observed in higher percentage of tumor area. CYP27B1 expression was lower in cancer cells than in normal epithelial cells (p = 0.03 with Mann–Whitney U test), but its expression did not correlate with tumor stage (pT), metastasizing, grade, mitotic activity or overall survival. In conclusion, expression of the VDR and CYP27B1 are deregulated in urothelial bladder cancers. Although our results showing a relationship between the decreased VDR expression and prognostic markers and survival time indicate potential usefulness of VDR as a new indicator of a poorer prognosis, further studies are needed in different patient cohorts by independent groups to validate this hypothesis. We also suggest that vitamin D-based therapies may represent an adjuvant strategy in treatment for bladder cancers expressing VDR.

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.

Investigation of the vitamin D receptor polymorphisms in acromegaly patients

Objective. The genetic structural alterations in the majority of somatotroph adenomas are not clarified and the search for novel candidate genes is still a challenge. We aimed to investigate possible associations between vitamin D receptor (VDR) polymorphisms and acromegaly. Design, Patients, and Methods. 52 acromegaly patients (mean age 45.7 ± 1.9 years) and 83 controls (mean age 43.1 ± 2.6 years) were recruited to the study. VDR polymorphism was determined by polymerase chain reaction-based restriction fragment length polymorphism methods. Results. The distribution of VDR genotypes showed a significant difference in the frequencies of VDR FokI genotypes between patients and controls (P = 0.034). VDR FokI ff genotype was significantly decreased in acromegaly patients (P = 0.035) and carriers of FokI Ff genotype had a 1.5-fold increased risk for acromegaly (OR: 1.5, 95% CI: 1.07–2.1; P = 0.020). IGF1 levels after treatment were significantly higher in patients carrying the Ff genotype compared to carrying ff genotype (P = 0.0049). 25(OH)D3 levels were significantly lower in acromegaly patients (P < 0.001). Conclusions. Our study suggests that VDR FokI genotypes might affect the development of acromegaly and VDR polymorphisms may play a role in the course of acromegaly as a consequence of altering hormonal status.

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.

Association of vitamin D receptor FokI and ApaI polymorphisms with lung cancer risk in Tunisian population

Many studies reported that Vitamin D Receptor (VDR) gene polymorphisms might influence the cancer risk due to their antiproliferative, antiangiogenic, and apoptotic effects. The aim of this study was to explore the genetic association of VDR polymorphisms with lung cancer risk in Tunisian population. The genotype and haplotype frequencies of four VDR polymorphisms, FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236) were studied using polymerase chain reaction and restriction fragment length polymorphism analysis in 240 patients with lung cancer and 280 healthy controls. The distribution of genotype frequencies differed significantly between lung cancer subjects and controls (FokI P adj = 0.002; ApaI P adj = 0.013). Haplotype analyses revealed a significant association between G-A-C and A-C-T haplotypes and lung cancer risk (P corr = 0.0128, P corr = 0.008). When patients were stratified according to gender, age, and smoking, significant associations were detected with FokI and TaqI polymorphisms. We found a lack of association between BsmI, TaqI polymorphisms and lung cancer risk (P > 0.05). Only, the attributable proportion due to interaction and the synergic index for interaction between ApaI polymorphism and smoking were statistically significant (P adj = 0.74, 95 % CI = 0.38-1.20) and (P adj = 0.63, 95 % CI = 0.05-1.21), respectively. Both the additive interaction measures suggested the existence of a biological interaction between SNP ApaI, but not FokI, and smoking. The multiplicative interaction measure was not statistically significant (P > 0.05). This is the first study in Tunisia, which suggested that VDR FokI and ApaI polymorphisms might be risk factors for lung cancer development.

The vitamin D receptor (VDR) gene polymorphisms in Turkish brain cancer patients

Objective. It has been stated that brain cancers are an increasingly serious issue in many parts of the world. The aim of our study was to determine a possible relationship between Vitamin D receptor (VDR) gene polymorphisms and the risk of glioma and meningioma. Methods. We investigated the VDR Taq-I and VDR Fok-I gene polymorphisms in 100 brain cancer patients (including 44 meningioma cases and 56 glioma cases) and 122 age-matched healthy control subjects. This study was performed by polymerase chain reaction-based restriction fragment length polymorphism (RF LP). Results. VDR Fok-I ff genotype was significantly increased in meningioma patients (15.9%) compared with controls (2.5%), and carriers of Fok-I ff genotype had a 6.47-fold increased risk for meningioma cases. There was no significant difference between patients and controls for VDR Taq-I genotypes and alleles. Conclusions. We suggest that VDR Fok-I genotypes might affect the development of meningioma.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

Influence of vitamin D binding protein on the association between circulating vitamin D and risk of bladder cancer

BACKGROUND

There is little research investigating the role of vitamin D binding protein (DBP) in the association between 25-hydroxyvitamin D (25(OH)D) and disease risk.

METHODS

Within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, 250 bladder cancer cases were randomly sampled and matched 1:1 to controls on age and date of blood collection. Odds ratios (OR) and 95% confidence intervals (CI) of bladder cancer were estimated by quartiles of DBP (measured by ELISA), 25(OH)D and the molar ratio of 25(OH)D:DBP, a proxy for free circulating 25(OH)D. Analyses were also conducted stratifying 25(OH)D by DBP (median split) and vice versa.

RESULTS

We found no direct association between circulating DBP levels and bladder cancer risk (P-trend=0.83). The inverse association between 25(OH)D and bladder cancer risk was unchanged after adjustment for DBP (Q4 vs Q1 OR=0.61, 95% CI=0.36-1.05; P-trend=0.04), and was stronger among men with lower DBP (low DBP: 25(OH)D Q4 vs Q1 OR=0.47, 95% CI=0.23-1.00; high DBP: 25(OH)D Q4 vs Q1 OR=0.83, 95% CI=0.40-1.75; P for interaction=0.11).

CONCLUSION

Our findings provide additional support for an aetiologic role for vitamin D in bladder cancer and suggest that free, rather than total, circulating vitamin D may be a more relevant exposure when examining bladder and, perhaps, other cancers.

Serum vitamin D and risk of bladder cancer

Vitamin D may protect against several cancers, but data about the association between circulating vitamin D and bladder cancer are limited. Within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a randomized controlled trial conducted to determine the effects of α-tocopherol and β-carotene supplements on cancer incidence in male smokers, 250 bladder cancer cases were randomly sampled by month of blood collection. Controls were matched 1:1 to cases on age at randomization and date of blood collection. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) of bladder cancer by a priori categories of baseline serum 25-hydroxyvitamin D [25(OH)D; i.e., <25, 25 to <37.5, 37.5 to <50, ≥50 nmol/L] and by season-specific quartiles. After multivariable adjustment, we found that lower 25(OH)D was associated with a statistically significantly increased risk of bladder cancer (versus ≥50 nmol/L; <25 nmol/L: OR, 1.73; 95% CI, 1.03-2.91; 25 to <37.5 nmol/L: OR, 1.81; 95% CI, 1.05-3.14; 37.5 to <50 nmol/L: OR, 1.76; 95% CI, 1.02-3.02; P trend=0.04). Similarly, increased risks for the lowest vitamin D category were observed when season-specific quartiles were used (Q1 versus Q4: OR, 1.63; 95% CI, 0.96-2.75; P trend=0.03). In this prospective study of male smokers, lower serum 25(OH)D was associated with an increased risk of bladder cancer. Future studies should examine the association in other populations, especially nonsmokers and women.

The beneficial role of vitamin D and its analogs in cancer treatment and prevention

BACKGROUND

Cancer is the leading cause of death in the United States, and the probability of developing cancer increases dramatically with age. Interestingly, vitamin D deficiency is also recognized more often in people of advanced ages. A potential relationship between vitamin D deficiency and cancer has been reported in the literature.

METHOD

Review Medline database literature and discuss the relationship between vitamin D status and cancer.

RESULTS

Environmental (including seasonal and geographic) and genetic factors contribute to the development of both vitamin D deficiency and cancer. The vitamin D receptor is present in many tissues, especially in malignant cells, and may contribute to the successful use of vitamin D and its analogs in the treatment of some cancer patients.

CONCLUSION

Further investigation of the role of vitamin D in the treatment of cancer is warranted.