Vitamin D pathway gene variants and prostate cancer prognosis

The double disparity: Vitamin D deficiency and lethal prostate cancer in black men

Epidemiological data from as early as the 1930s documented a dramatic racial disparity in prostate cancer incidence, survival, and mortality rates among Black men-a trend that persists to this day. Black men are disproportionately burdened by prostate cancer, developing the disease at younger ages, facing more aggressive and lethal forms, and ultimately experiencing double the mortality rate of men of European descent. Investigating the multifactorial contributors to this racial disparity has been extensive, but results have often been inconsistent or inconclusive, making it difficult to pinpoint clear correlations. However, there is strong evidence suggesting that vitamin D deficiency is significantly associated with lethal forms of prostate cancer. This is particularly important given that Black men are at a higher risk for both vitamin D deficiency and developing aggressive, lethal prostate cancer, presenting a double disparity. The disparity in prostate cancer and vitamin D extends to Black men outside the US, but most of the studies have been done in African American men. Understanding the available evidence on vitamin D deficiency and its influence on prostate cancer biology may reveal new opportunities for prevention and therapeutic intervention.

Vitamin D-related genetic variants and prostate cancer risk in Black men

BACKGROUND

The relationship between vitamin D and prostate cancer has primarily been characterized among White men. Black men, however, have higher prostate cancer incidence and mortality rates, chronically low circulating vitamin D levels, and ancestry-specific genetic variants in vitamin D-related genes. Here, we examine critical genes in the vitamin D pathway and prostate cancer risk in Black men.

METHODS

We assessed a total of 73 candidate variants in genes (namely GC, CYP27A1, CYP27B1, CYP24A1, VDR, and RXRA) including functional variants previously associated with prostate cancer and circulating 25(OHD) in White men. Associations with prostate cancer risk were examined using genome-wide association study data for approximately 10,000 prostate cancer cases and 10,000 controls among Black men and over 85,000 cases and 91,000 controls among White men for comparison. A statistical significance threshold of 0.000685 was used to account for the 73 variants tested.

RESULTS

None of the variants examined were significantly associated with prostate cancer risk among Black men after multiple comparison adjustment. Suggestive associations (P < 0.05) for four variants were found in Black men, including two in RXRA (rs41400444 OR=1.09, 95 % CI: 1.01-1.17, P = 0.024 and rs10881574 OR = 0.93, 0.87-1.00, P = 0.046) and two in VDR (rs2853563 OR = 1.07, 1.01-1.13, P = 0.017 and rs1156882 OR = 1.06, 1.00-1.12, P = 0.045). Two variants in VDR were also positively associated with risk in White men (rs11568820 OR = 1.04, 1.02-1.06, P = 0.00024 and rs4516035 OR = 1.03, 1.01-1.04, P = 0.00055).

CONCLUSION

We observed suggestive associations between genetic variants in RXRA and VDR and prostate cancer risk in Black men. Future research exploring the relationship of vitamin D with cancer risk in Black men will need larger sample sizes to identify ancestry-specific variants relevant to risk in this population.

Regulatory mechanisms and pathological implications of CYP24A1 in Vitamin D metabolism

CYP24A1 is a crucial gene within the cytochrome P450 superfamily, responsible for encoding the enzyme 25-hydroxyvitamin D3-24-hydroxylase. This enzyme is involved in the catabolism of 1,25-dihydroxyvitamin D3, the biologically active form of vitamin D3, by hydroxylating its side chain. Through this process, CYP24A1 tightly regulates the bioavailability and physiological impact of vitamin D3 in the body. Dysregulation of CYP24A1, particularly its overexpression, has been increasingly associated with the progression of various diseases, including cancers, autoimmune disorders, and chronic inflammatory conditions. Elevated levels of CYP24A1 can lead to excessive degradation of vitamin D3, resulting in diminished levels of this critical hormone, which is essential for calcium homeostasis, immune function, and cellular proliferation. This review explores into the structural characteristics of CYP24A1, exploring how it influences its enzymatic activity. Furthermore, it examines the expression patterns of CYP24A1 across different diseases, emphasizing the enzyme's role in disease pathology. The review also discusses the regulatory mechanisms governing CYP24A1 expression, including genetic mutations, epigenetic modifications, and metabolite-mediated regulation. By understanding these mechanisms, the review provides insight into the potential therapeutic strategies that could target CYP24A1, aiming to alleviate its overexpression and restore vitamin D3 balance in disease states.

Vitamin D receptor polymorphisms and associated miRNAs in the development of breast cancer in African American women

Breast cancer (BCa) is a prevalent form of cancer in women, exhibiting varying rates and distribution across different ethnic groups. Among these groups, African American (AA) women have the highest incidence of BCa and the lowest levels of Vitamin D (VD). Numerous studies have explored the connection between variations in the VDR gene and BCa risk, particularly in different populations, but research on the AA population remains limited. Epigenetic modifications, including specific microRNAs (miRNAs), can influence gene expression without altering the genetic code and have been implicated in cancer initiation and progression. Our hypothesis suggests that VDR gene variations may increase BCa risk in AA women and that changes in miRNA expression profiles could contribute to BCa development. Using data from the 1000 Genome Project, we identified five VDR gene variants with significant frequency differences between AA and European-American (EA) populations. We genotyped 404 African American BCa cases and controls for five variants using TaqMan® assays. SNPstats assessed their association with BCa risk. The rs1544410 variant's recessive model (A/A) showed a decreased BCa risk in AA (odds ratio 0.33, 95% CI: 0.15-0.73, p-value 0.0041). Conversely, the rs2853563 variant's recessive model (A/A) was linked to an increased BCa risk (odds ratio 4.04, 95% CI: 1.49-10.95, p-value 0.0022). We investigated miRNA expression influenced by VD in HCC1806 Triple-Negative Breast Cancer (TNBC) cell lines with the A/A allele for rs2853563. nCounter® Nanostring technology assessed miRNA profiles after calcitriol treatment. Our results indicated that calcitriol treatment led to reduced expression of six miRNAs, four of which are associated with tumor suppression in the presence of the AA genotype in TNBC cell lines. These findings suggest that specific VDR genotypes could have a potential effect on the miRNAs expression which could potentially serve as markers for cell proliferation in TNBC.

Intratumoral vitamin D signaling and lethal prostate cancer

High circulating vitamin D levels and supplementation may lower prostate cancer mortality. To probe for direct effects of vitamin D signaling in the primary tumor, we assessed how activation of intratumoral vitamin D signaling in prostate cancer is associated with lethal prostate cancer during long-term follow-up. Among 404 participants with primary prostate cancer in the Health Professionals Follow-up Study and the Physicians' Health Study, we defined a gene score of expected activated intratumoral vitamin D signaling consisting of transcriptionally upregulated (CYP27A1, CYP2R1, RXRA, RXRB, and VDR) and downregulated genes (CYP24A1 and DHCR7). We contrasted vitamin D signaling in tumors that progressed to lethal disease (metastases/prostate cancer-specific death, n = 119) over up to three decades of follow-up with indolent tumors that remained nonmetastatic for >8 years post-diagnosis (n = 285). The gene score was downregulated in tumor tissue compared with tumor-adjacent histologically normal tissue of the same men. Higher vitamin D gene scores were inversely associated with lethal prostate cancer (odds ratio for highest versus lowest quartile: 0.46, 95% confidence interval: 0.21-0.99) in a dose-response fashion and after adjusting for clinical and pathologic factors. This association appeared strongest among men with high predicted plasma 25-hydroxyvitamin D3 and men with body mass index ≥25 kg/m2. Findings were replicated with broader gene sets. These data support the hypothesis that active intratumoral vitamin D signaling is associated with better prostate cancer outcomes and provide further rationale for testing how vitamin D-related interventions after diagnosis could improve prostate cancer survival through effects on the tumor.

Variants in Vitamin D-related Genes and Prostate Cancer Risk in Black Men

BACKGROUND

The relationship between vitamin D and prostate cancer has primarily been characterized among White men. However, Black men have higher prostate cancer incidence and mortality rates, chronically low circulating vitamin D levels, and ancestry-specific genetic variants in vitamin D-related genes. Here, we examine six critical genes in the vitamin D pathway and prostate cancer risk in Black men.

METHODS

We assessed a total of 69 candidate variants in six genes ( GC, CYP27A1, CYP27B1, CYP24A1, VDR , and RXRA ) including functional variants previously associated with prostate cancer and circulating 25(OHD) in White men. Associations with prostate cancer risk were examined using genome-wide association study data for approximately 10,000 prostate cancer cases and 10,000 controls among Black men and over 85,000 cases and 91,000 controls among White men. A statistical significance threshold of 0.000724 was used to account for the 69 variants tested.

RESULTS

None of the variants examined were significantly associated with prostate cancer risk among Black men after multiple comparison adjustment. Four variants tested P<0.05 in Black men, including two in RXRA (rs41400444 OR=1.09, 95% CI: 1.01-1.17, P = 0.024 and rs10881574 OR = 0.93, 0.87-1.00, P = 0.046) and two in VDR (rs2853563 OR = 1.07, 1.01-1.13, P = 0.017 and rs1156882 OR = 1.06, 1.00-1.12, P = 0.045). Two variants in VDR were also positively associated with risk in White men (rs11568820 OR = 1.04, 1.02-1.06, P = 0.00024 and rs4516035 OR = 1.03, 1.01-1.04, P = 0.00055).

CONCLUSION

We observed suggestive non-significant associations between genetic variants in RXRA and VDR and prostate cancer risk in Black men. Future research exploring the relationship of vitamin D with cancer risk in Black men will need larger sample sizes to identify ancestry-specific variants relevant to risk in this population.

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 Deficiency at Diagnosis Increases All-Cause and Prostate Cancer-specific Mortality in Jamaican Men

Background

25 hydroxyvitamin D [25(OH)D] and serum calcium have been associated with incident prostate cancer (PCa). However, there is limited data on whether these metabolites predict survival in men of African descent, a population disproportionately affected by PCa. We studied the relationship of 25(OH)D at PCa diagnosis with all-cause and cancer-specific mortality among Jamaican men and examined whether serum calcium modified any associations.

Methods

Serum 25(OH)D from 152 Jamaican men with incident PCa within the Prostate Cancer Risk Evaluation (PROSCARE) study were re-evaluated approximately 11 years after enrollment. 25(OH)D analyses were stratified using the using Holick criteria. PCa-specific and all-cause mortality were examined in Kaplan–Meier survival curves and Cox regression models adjusted for age, body mass index (BMI), smoking and Gleason score. Restricted cubic splines evaluated nonlinear associations. Serum calcium was assessed as an effect modifier of the association between 25(OH)D and mortality.

Results

Of cases with available 25(OH)D, 64 men with PCa survived, 38 deaths were PCa specific and 36 died of other causes. At baseline, 9.9% of cases were vitamin D deficient and 61.2% were vitamin D sufficient. Compared to 25(OH)D sufficient men, those with 25(OH)D <20.0 ng/mL concentrations were associated with higher PCa-specific mortality (adjusted HR, 4.95; 95% CI, 1.68, 14.63, P = .004) and all-cause mortality (adjusted HR, 2.40; 95%CI, 1.33, 4. 32, P = .003). Serum calcium was not associated with survival and did not modify any associations with 25(OH)D.

Conclusions

25(OH)D deficiency at PCa diagnosis predicted decreased survival for overall and PCa-specific cancer in Caribbean men of African ancestry.

Association of CYP24A1 gene polymorphism with colorectal cancer in the Jiamusi population

BACKGROUND

The population in Jiamusi has been reported to have the highest prevalence of colorectal cancer (CRC) in China. The genetic causal-effect for this occurrence among the residents remains unclear. Given the long cold seasons with people wearing more clothes and reduced UV exposure, we aimed to study the association between the vitamin D metabolism-related gene CYP24A1 polymorphism and CRC susceptibility.

METHOD

A case-control study was conducted that included 168 patients with CRC and 710 age-matched healthy individuals as the control group. Plausible susceptible variations were sought and clinical phenotypic-genotype association analysis was performed.

RESULTS

Overall, two CYP24A1 polymorphisms, rs6013905 AX (P = 0.02, OR = 1.89, 95%CI: 1.09-3.29) and rs2762939 GX (P = 0.02, OR = 1.52, 95%CI: 1.08-2.13) were significantly associated with CRC in the Jiamusi population. In the female group, three CYP24A1 polymorphisms, rs6013905 AX (P = 0.04, OR = 2.59, 95%CI: 1.03-6.49), rs2762939 GX (P = 0.01, OR = 2.35, 95%CI: 1.25-4.42), and rs6068816 GG (P = 0.05, OR = 1.89, 95%CI: 0.99-3.59) carriers were significantly associated with CRC. In clinical phenotypic-genotype analysis, rs6013905 GG (P = 0.05, OR = 4.00, 95%CI: 0.92-17.48) and rs2762939 GX (P = 0.03, OR = 4.87, 95%CI: 1.00-23.69) carriers were significantly associated with poorly differentiated CRC, while CYP24A1 rs6068816 AX was significantly associated with the tumor type (P = 0.02, OR = 2.08, 95%CI: 1.10-3.96) and location (P = 0.04, OR = 2.24, 95%CI: 1.05-4.77).

CONCLUSION

CYP24A1 gene polymorphism may be a genetic risk factor attributable to the highest prevalence of CRC in Jiamusi people. Individuals with CYP24A1 gene polymorphism may have an increased barrier for vitamin D absorption, thus contributing to the risk of CRC development.

Glycan-Dependent and -Independent Dual Recognition between DC-SIGN and Type II Serine Protease MSPL/TMPRSS13 in Colorectal Cancer Cells

A class of glycoproteins such as carcinoembryonic antigen (CEA)/CEA-related cell adhesion molecule 1(CEACAM1), CD26 (DPPIV), and mac-2 binding protein (Mac-2BP) harbor tumor-associated glycans in colorectal cancer. In this study, we identified type II transmembrane mosaic serine protease large-form (MSPL) and its splice variant transmembrane protease serine 13 (TMPRSS13) as ligands of Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) on the colorectal cancer cells. DC-SIGN is a C-type lectin expressed on dendritic cells, serves as a pattern recognition receptor for numerous pathogens such as human immunodeficiency virus (HIV) and M. tuberculosis. DC-SIGN recognizes these glycoproteins in a Ca2+ dependent manner. Meanwhile, we found that MSPL proteolytically cleaves DC-SIGN in addition to the above glycan-mediated recognition. DC-SIGN was degraded more efficiently by MSPL when treated with ethylenediaminetetraacetic acid (EDTA), suggesting that glycan-dependent interaction of the two molecules partially blocked DC-SIGN degradation. Our findings uncovered a dual recognition system between DC-SIGN and MSPL/TMPRSS13, providing new insight into the mechanism underlying colorectal tumor microenvironment.

Single Nucleotide Polymorphisms in 25-Hydroxyvitamin D3 1-Alpha-Hydroxylase (CYP27B1) Gene: The Risk of Malignant Tumors and Other Chronic Diseases

: Vitamin D is widely known for its roles in the promotion of apoptosis and differentiation, with simultaneous inhibition of proliferation, inflammation, angiogenesis, invasion, and metastasis. Modern literature lacks complete information on polymorphisms in CYP27B1, the only enzyme capable of vitamin D activation. This review presents gathered data that relate to genetic variants in CYP27B1 gene in correlation to multiple diseases, mostly concerning colorectal, prostate, breast, lung, and pancreatic cancers, as well as on other pathologies, such as non-Hodgkin's lymphoma, oral lichen planus, or multiple sclerosis.

Vitamin D Pathway and Other Related Polymorphisms and Risk of Prostate Cancer: Results from the Prostate Cancer Prevention Trial

Vitamin D may influence prostate cancer risk, but evidence is inconsistent. We conducted a nested case-control study in the Prostate Cancer Prevention Trial (PCPT). Cases (n = 1,128) and controls (n = 1,205) were frequency matched on age, first-degree relative with prostate cancer, and PCPT treatment arm (finasteride/placebo); African-Americans were oversampled and case/control status was biopsy confirmed. We selected 21 SNPs in vitamin D-related genes (VDR, GC, C10orf88, CYP2R1, CYP24A1, CYP27B1, DHCR7, and NADSYN1) to test genotype and genotype-treatment interactions in relation to prostate cancer. We also tested mean serum 25(OH)D differences by minor allele distributions and tested for serum 25(OH)D-genotype interactions in relation to prostate cancer risk. Log-additive genetic models (Bonferroni-corrected within genes) adjusted for age, body mass index, PSA, and family history of prostate cancer revealed a significant interaction between treatment arm and GC/rs222016 (finasteride OR = 1.37, placebo OR = 0.85; P _interaction < 0.05), GC/rs222014 (finasteride OR = 1.36, placebo OR = 0.85; P _interaction < 0.05), and CYP27B1/rs703842 (finasteride OR = 0.76, placebo OR = 1.10; P _interaction < 0.05) among Caucasians, and C10orf88/rs6599638 (finasteride OR = 4.68, placebo OR = 1.39; P _interaction < 0.05) among African-Americans. VDR/rs1544410 and CYP27B1/rs703842 had significant treatment interactions for high-grade disease among Caucasians (finasteride OR = 0.81, placebo OR = 1.40; P _interaction < 0.05 and finasteride OR = 0.70, placebo OR = 1.28; P _interaction < 0.05, respectively). Vitamin D-related SNPs influenced serum 25(OH)D, but gene-serum 25(OH)D effect modification for prostate cancer was marginally observed only for CYP24A1/rs2248359. In conclusion, evidence that vitamin D-related genes or gene-serum 25(OH)D associations influence prostate cancer risk is modest. We found some evidence for gene-finasteride interaction effects for prostate cancer in Caucasians and African-Americans. Results suggest only minimal associations of vitamin D with total or high-grade prostate cancer.

Diet and Lifestyle in Prostate Cancer

A variety of diet and lifestyle factors have been studied with respect to prostate cancer risk in large, prospective cohort studies. In spite of this work, and in contrast to other common cancers, few modifiable risk factors have been firmly established as playing a role in prostate cancer. There are several possible explanations for the lack of well-established risk factors. First, prostate cancer has among the highest heritability of all common cancers; second, early life exposures may play an important role in risk, rather than mid- and later-life exposures assessed in most epidemiological studies. Finally, prostate-specific antigen (PSA) screening plays a critical role in prostate cancer detection and incidence rates, which has important implications for epidemiological studies.Among modifiable risk factors, smoking and obesity are consistently associated with higher risk specifically of advanced prostate cancer. There is also considerable evidence for a positive association between dairy intake and overall prostate cancer risk, and an inverse association between cooked tomato/lycopene intake and risk of advanced disease. Several other dietary factors consistently associated with risk in observational studies, including selenium and vitamin E, have been cast into doubt by results from clinical trials. Results for other well-studied dietary factors, including fat intake, red meat, fish, vitamin D, soy and phytoestrogens are mixed.In practical terms, men concerned with prostate cancer risk should be encouraged to stop smoking, be as physically active as possible, and achieve or maintain a healthy weight. These recommendations also have the advantage of having a positive impact on risk of type 2 diabetes, cardiovascular disease, and other chronic diseases. Reducing dairy intake while increasing consumption of fish and tomato products is also reasonable advice.

Germline Polymorphisms in the Nuclear Receptors PXR and VDR as Novel Prognostic Markers in Metastatic Colorectal Cancer Patients Treated With FOLFIRI

Nuclear receptors act as mediators of cancer-related inflammation and gene expression. They have a regulatory effect on genes encoding proteins related to drug adsorption, distribution, metabolism, and excretion. The aim of the present study was to highlight novel prognostic markers among polymorphisms in genes encoding for nuclear receptor proteins and inflammation-related cytokines in patients treated with a FOLFIRI regimen. This study included two independent cohorts comprising a total of 337 mCRC patients homogeneously treated with first-line FOLFIRI. Genotyping of 246 haplotype-tagging polymorphisms in 22 genes was performed using bead array technology. The NR1I2 (PXR)-rs1054190 and VDR-rs7299460 polymorphisms were significantly associated with patient overall survival (OS). A detrimental effect of the NR1I2 rs1054190-TT genotype on OS was observed in both the discovery and replication cohorts (HR = 6.84, P = 0.0021, q-value = 0.1278 and HR = 3.56, P = 0.0414, respectively). Patients harboring the NR1I2 rs1054190-TT genotype had a median OS of 9 months vs. 21 months in patients with C-allele (P < 0.0001 log-rank test). VDR rs7299460-T was consistently associated with a longer OS in both cohorts (discovery: HR = 0.61, P = 0.0075, q-value = 0.1535; replication: HR = 0.57, P = 0.0477). Patients with the VDR rs7299460-T allele had a median OS of 23 months compared to 18 months in those with the CC genotype (P = 0.0489, log-rank test). The NR1I2-rs1054190 polymorphism also had an effect on the duration of progression-free survival, consistent with the effect observed on OS. Two novel prognostic markers for mCRC treated with FOLFIRI were described and, if validated by prospective trials, have a potential application in the management of these patients.

Phytochemicals in Prostate Cancer: From Bioactive Molecules to Upcoming Therapeutic Agents

Prostate cancer is a heterogeneous disease, the second deadliest malignancy in men and the most commonly diagnosed cancer among men. Traditional plants have been applied to handle various diseases and to develop new drugs. Medicinal plants are potential sources of natural bioactive compounds that include alkaloids, phenolic compounds, terpenes, and steroids. Many of these naturally-occurring bioactive constituents possess promising chemopreventive properties. In this sense, the aim of the present review is to provide a detailed overview of the role of plant-derived phytochemicals in prostate cancers, including the contribution of plant extracts and its corresponding isolated compounds.

Sex-specific role of CYP24A1 rs2762939 in the risk of essential hypertension based on the serum vitamin D and total renin concentrations

CYP24A1, Vitamin D 24-hydroxylase catabolizes 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D to 24-hydroxylated vitamin D products. It is widely known that low Vitamin D can lead to increased renal renin and angiotensin II production, consequently elevating blood pressure or development of essential hypertension (EH). We have conducted an investigation on hypertensives and controls to evaluate the association of the gene variant, CYP24A1 rs2762939 and 25(OH)D in an Indian population with EH. On gender-based stratification, with multivariate logistic analysis after adjustment for covariates, the CYP24A1 rs2762939 CC variant showed a higher risk of EH in males (aOR = 3.141, CI 1.164-8.478, P = .024) while females illustrated an inverse association with EH (aOR = 0.398, CI 0.172-0.092, P = .031). The 25(OH)D levels among the three genotypes of hypertensives substantiate these results. Our results clearly suggest that gender, CYP24A1 rs2762939, and Vitamin D status may play a significant role in disease susceptibility towards EH in Indian population.

CYP24A1 genetic variants in the vitamin D metabolic pathway are involved in the outcomes of hepatitis C virus infection among high-risk Chinese population

BACKGROUND AND AIMS

It has been demonstrated that 1,25-hydroxyvitamin-D3-24-hydroxylase, encoded by CYP24A1 gene, is a key enzyme that neutralizes the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] in response to hepatitis C virus (HCV) infection. This study aimed to investigate whether CYP24A1 genetic variation is associated with HCV infection outcomes.

METHODS

848 HCV chronically infected subjects, 507 natural clearance subjects, and 1017 uninfected controls were enrolled. Nine single nucleotide polymorphisms (SNPs) in theCYP24A1 gene were genotyped using the Sequenom MassARRAY platform.

RESULTS

After adjusting for age, gender, and routes of infection, logistic regression analyses showed that rs6013897-A was associated with an elevated risk of HCV infection (P<0.05). In addition, this study has also demonstrated that rs6068816-T significantly reduced the risk of chronic HCV infection, while rs3787557-C, rs6022999-G, and rs2248359-T significantly increased the risk of chronic HCV infection (all P<0.05). Haplotype analysis suggested that, compared to the most frequent T_rs6068816T_rs3787557A_rs6022999C_rs2248359 haplotype, the CTGT haplotype (adjusted OR=1.376, 95% CI=1.092-1.735, P=0.007) and CCAC haplotype (adjusted OR=1.483, 95% CI=1.139-1.929, P=0.003) were associated with an increased risk of chronic HCV infection.

CONCLUSION

These findings indicate that SNPs in CYP24A1 gene may contribute to the risk of HCV infection and chronic HCV infection among a high-risk Chinese population.

Role of CYP1A1, ABCG2, CYP24A1 and VDR gene polymorphisms on the evaluation of cardiac iron overload in thalassaemia patients

OBJECTIVES

Iron-burden-induced arrhythmia and heart failure are among the leading causes of morbidity and mortality in β-thalassaemia major patients. T2* cardiac magnetic resonance remains the only reliable noninvasive method for the heart iron excess assessment. We explored the role of single nucleotide polymorphisms involved in vitamin D metabolism, transport and activity and in deferasirox (DFX) metabolism on cardiac iron burden.

PATIENTS AND METHODS

One hundred and five β-thalassaemia patients, treated with DFX, were enrolled in the present study. Drug plasma Ctrough was measured by a high-performance liquid chromatography-ultraviolet method. Allelic discrimination was carried out using the real-time PCR.

RESULTS

CYP1A1*1189 CC, ABCG2 421 GA, CYP24A1 8620 GG and VDR TaqI CC single nucleotide polymorphisms influenced T2* values. Age, serum ferritin, ABCG2 421 GA, ABCG2 1194 +928 TC/CC, CYP24A1 22776 TT and VDR TaqI TC/CC were retained in linear regression model.

CONCLUSION

Our results suggested, for the first time, the role of DFX and vitamin D pharmacogenetics on cardiac iron overload.

The Epidemiology of Prostate Cancer

Prostate cancer is a major cause of disease and mortality among men, and each year 1.6 million men are diagnosed with and 366,000 men die of prostate cancer. In this review, we discuss the state of evidence for specific genetic, lifestyle, and dietary factors associated with prostate cancer risk. Given the biological heterogeneity of this cancer, we focus on risk factors for advanced or fatal prostate cancer. First, we provide descriptive epidemiology statistics and patterns for prostate cancer incidence and mortality around the world. This includes discussion of the impact of prostate-specific antigen screening on prostate cancer epidemiology. Next, we summarize evidence for selected risk factors for which there is strong or probable evidence of an association: genetics, obesity and weight change, physical activity, smoking, lycopene and tomatoes, fish, vitamin D and calcium, and statins. Finally, we highlight future directions for prostate cancer epidemiology research.

Circulating vitamin D level and mortality in prostate cancer patients: a dose-response meta-analysis

Previous studies investigating the association of circulating 25-hydroxyvitamin D level with prognosis of prostate cancer yielded controversial results. We conducted a dose-response meta-analysis to elucidate the relationship. PubMed and EMBASE were searched for eligible studies up to July 15, 2018. We performed a dose-response meta-analysis using random-effect model to calculate the summary hazard ratio (HR) and 95% CI of mortality in patients with prostate cancer. Seven eligible cohort studies with 7808 participants were included. The results indicated that higher vitamin D level could reduce the risk of death among prostate cancer patients. The summary HR of prostate cancer-specific mortality correlated with an increment of every 20 nmol/L in circulating vitamin D level was 0.91, with 95% CI 0.87-0.97, P = 0.002. The HR for all-cause mortality with the increase of 20 nmol/L vitamin D was 0.91 (95% CI: 0.84-0.98, P = 0.01). Sensitivity analysis suggested the pooled HRs were stable and not obviously changed by any single study. No evidence of publications bias was observed. This meta-analysis suggested that higher 25-hydroxyvitamin D level was associated with a reduction of mortality in prostate cancer patients and vitamin D is an important protective factor in the progression and prognosis of prostate cancer.

Genetic risk factors for post-transplantation diabetes mellitus in Chinese Han renal allograft recipients treated with tacrolimus

BACKGROUND

Post-transplantation diabetes mellitus (PTDM) is a serious metabolic complication after kidney transplantation. The aim of this study was to explore the association of clinical variables and five selected single nucleotide polymorphisms (SNPs) with PTDM in Chinese Han renal allograft recipients taking tacrolimus (TAC).

METHODS

A total of 129 non-diabetic, primary, Chinese Han renal allograft recipients treated with TAC were enrolled. Five SNPs (CYP3A5 rs776741, rs776746, rs15524, CYP24A1 rs2296241, and PPARG rs1801282) were genotyped and analyzed.

RESULTS

Among 129 recipients, 17 (13.2%) developed PTDM. Both univariate and multivariate analysis demonstrated that age over 50 years old and CYP24A1 rs2296241 A allele were independently correlated with the development of PTDM, while no significant differences was observed in TAC pharmacokinetics and CYP3A5, PPARG polymorphisms between two groups.

CONCLUSIONS

Patients with advanced age and CYP24A1 rs2296241 A allele had an increased risk of PTDM after kidney transplantation.

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.

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

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

Impact of phosphoinositide-3-kinase and vitamin D3 nuclear receptor single-nucleotide polymorphisms on the outcome of malignant melanoma patients

Background

Several studies associating single nucleotide polymorphisms (SNPs) frequencies with tumors outcome have been conducted, nevertheless malignant melanoma literature data are inconclusive.

Therefore we evaluate the impact of different genotypes for phosphoinositide-3-kinase (PI3K) and vitamin D3 nuclear receptor (VDR) SNPs on melanoma patients’ outcome.

Materials and methods

Genomic DNA of 88 patients was extracted from blood and tumor samples. SNPs were determined by PCR using TaqMan assays. We selected polymorphisms of the regulatory and catalytic subunit of PI3K (PIK3R1 and PIK3CA genes, respectively), analyzing rs2699887C>T of PIK3CA and rs3730089G>A of PIK3R1 SNPs. Furthermore we considered the following VDR SNPs: rs2228570A>G (Fok1), rs731236A>G (Taq1) and rs1544410C>T (Bsm1).

Progression free survival (PFS) and overall survival (OS) were estimated with the Kaplan-Meier method and with Mantel-Haenszel log-rank test.

Results

The statistical analysis for Fok1 of VDR showed a significant difference in PFS after the first line therapy (median PFS= 21.2 months in the homozygous recessive genotype group vs. 3.3 months of homozygous dominant and heterozygous ones, p= 0.03). In particular, in homozygous recessive patients for Fok1 SNPs of VDR a high rate of histological regression and BRAF (B- Rapidly Accelerated Fibrosarcoma gene) mutation were observed. Furthermore, more efficacy of BRAF +/- MEK (MAPK-ERK-Kinase) inhibitors therapies in homozygous recessive patients vs. homozygous dominant and heterozygous ones was shown.

Conclusions

Our study showed a significant correlation between homozygous recessive genotype of Fok1 SNPs of VDR gene and an increased PFS in patients who underwent a first line therapy with BRAF inhibitors.

Ferguson L. SNP-SNP interactions as risk factors for aggressive prostate cancer

Prostate cancer (PCa) is one of the most significant male health concerns worldwide. Single nucleotide polymorphisms (SNPs) are becoming increasingly strong candidate biomarkers for identifying susceptibility to PCa. We identified a number of SNPs reported in genome-wide association analyses (GWAS) as risk factors for aggressive PCa in various European populations, and then defined SNP-SNP interactions, using PLINK software, with nucleic acid samples from a New Zealand cohort. We used this approach to find a gene x environment marker for aggressive PCa, as although statistically gene x environment interactions can be adjusted for, it is highly impossible in practicality, and thus must be incorporated in the search for a reliable biomarker for PCa. We found two intronic SNPs statistically significantly interacting with each other as a risk for aggressive prostate cancer on being compared to healthy controls in a New Zealand population.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Tumor-suppressive activity of 1,25-dihydroxyvitamin D3 against kidney cancer cells via up-regulation of FOXO3

1,25-Dihydroxyvitamin D3 has been known to have the tumor-suppressive activity in various kinds of tumors. However, the exact effect and working mechanism of 1,25-dihydroxyvitamin D3 on the tumor-suppressive activity in human kidney cancer cells remains poorly understood. 1,25-Dihydroxyvitamin D3 has cytotoxicity to ACHN cells and inhibited ACHN cell proliferation compared to the vehicle control. 1,25-Dihydroxyvitamin D3 increased the expression of the cleaved PARP1, active Caspase3, Bax, and Bim but decreased the expression of Bcl2 in ACHN cells. Moreover, 1,25-dihydroxyvitamin D3 down-regulated the phosphorylated Akt and Erk which might lead to apoptosis through activation of FOXO3 in ACHN cells. Transfection of siRNA against FOXO3 attenuated the pro-apoptotic BimEL expression in ACHN cells treated with 1,25-dihydroxyvitamin D3. These results suggest that FOXO3 is involved in the apoptosis induced by 1,25-dihydroxyvitamin D3.

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

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

Calcitriol in Combination Therapy for Prostate Cancer: Pharmacokinetic and Pharmacodynamic Interactions

Epidemiological studies indicate that vitamin D insufficiency could have an etiological role in prostate cancer. In addition, calcitriol, used in combination with currently available drugs, has the potential to potentiate their anticancer effects or act synergistically by inhibiting distinct mechanisms involved in prostate cancer growth. Clinical data have not yet provided sufficient evidence to demonstrate benefit of vitamin D due to the limited and underpowered studies that have been published to date. Here, we review the preclinical and clinical studies that describe the activity of calcitriol, applied either alone or in combination and assessed the mechanistic basis of pharmacodynamic and pharmacokinetic interactions with calcitriol. Important considerations for calcitriol use in combination therapy with respect to safety and clinical outcomes have been discussed. Many of these combinations have therapeutic potential for the treatment of several cancer types and it is anticipated that future clinical research will put emphasis on well‑designed clinical trials to establish efficacy.

A prospective study of plasma 25-hydroxyvitamin D concentration and prostate cancer risk

Mechanistic hypotheses suggest that vitamin D and the closely related parathyroid hormone (PTH) may be involved in prostate carcinogenesis. However, epidemiological evidence is lacking for PTH and inconsistent for vitamin D. Our objectives were to prospectively investigate the association between vitamin D status, vitamin D-related gene polymorphisms, PTH and prostate cancer risk. A total of 129 cases diagnosed within the Supplémentation en Vitamines et Minéraux Antioxydants cohort were included in a nested case-control study and matched to 167 controls (13 years of follow-up). 25-Hydroxyvitamin D (25(OH)D) and PTH concentrations were assessed from baseline plasma samples. Conditional logistic regression models were computed. Higher 25(OH)D concentration was associated with decreased risk of prostate cancer (ORQ4 v. Q1 0·30; 95 % CI 0·12, 0·77; P trend=0·007). PTH concentration was not associated with prostate cancer risk (P trend=0·4) neither did the studied vitamin D-related gene polymorphisms. In this prospective study, prostate cancer risk was inversely associated with 25(OH)D concentration but not with PTH concentration. These results bring a new contribution to the understanding of the relationship between vitamin D and prostate cancer, which deserves further investigation.

Vitamin D receptor polymorphisms and survival in patients with cutaneous melanoma: a population-based study

Factors known to affect melanoma survival include age at presentation, sex and tumor characteristics. Polymorphisms also appear to modulate survival following diagnosis. Result from other studies suggest that vitamin D receptor (VDR) polymorphisms (SNPs) impact survival in patients with glioma, renal cell carcinoma, lung, breast, prostate and other cancers; however, a comprehensive study of VDR polymorphisms and melanoma-specific survival is lacking. We aimed to investigate whether VDR genetic variation influences survival in patients with cutaneous melanoma. The analysis involved 3566 incident single and multiple primary melanoma cases enrolled in the international population-based Genes, Environment, and Melanoma Study. Melanoma-specific survival outcomes were calculated for each of 38 VDR SNPs using a competing risk analysis after adjustment for covariates. There were 254 (7.1%) deaths due to melanoma during the median 7.6 years follow-up period. VDR SNPs rs7299460, rs3782905, rs2239182, rs12370156, rs2238140, rs7305032, rs1544410 (BsmI) and rs731236 (TaqI) each had a statistically significant (trend P values < 0.05) association with melanoma-specific survival in multivariate analysis. One functional SNP (rs2239182) remained significant after adjustment for multiple testing using the Monte Carlo method. None of the SNPs associated with survival were significantly associated with Breslow thickness, ulceration or mitosis. These results suggest that the VDR gene may influence survival from melanoma, although the mechanism by which VDR exerts its effect does not seem driven by tumor aggressiveness. Further investigations are needed to confirm our results and to understand the relationship between VDR and survival in the combined context of tumor and host characteristics.

CYP24A1 and CYP27B1 Polymorphisms, Concentrations of Vitamin D Metabolites, and Odds of Colorectal Adenoma Recurrence

Development of colorectal adenoma and cancer are associated with low circulating 25-hydroxyvitamin D [25(OH)D] levels. However, less is known regarding colorectal neoplasia risk and variation in CYP27B1 or CYP24A1, genes encoding the enzymes responsible for the synthesis and catabolism of 1α,25-hydroxyvitamin D [1,25(OH)2D]. This study examined associations between CYP27B1 and CYP24A1 polymorphisms, circulating 25(OH)D and 1,25(OH)2D concentrations, and colorectal adenoma recurrence in a pooled sample from 2 clinical trials (n = 1,188). Nominal associations were observed between increasing copies of the T allele in CYP24A1 rs927650 and 25(OH)D concentrations (P = 0.02); as well as colorectal adenoma recurrence, with odds ratios (95% confidence intervals) of 1.30 (0.99-1.70) and 1.38 (1.01-1.89) for heterozygotes and minor allele homozygotes, respectively (P = 0.04). In addition, a statistically significant relationship between CYP24A1 rs35051736, a functional polymorphism, and odds for advanced colorectal adenoma recurrence was observed (P < 0.001). Further, nominally statistically significant interactions were observed between rs2296241 and 25(OH)D as well as rs2762939 and 1,25(OH)2D (P(interaction) = 0.10, respectively). Overall, CYP24A1 polymorphisms may influence the development of advanced lesions, and modify the effect of vitamin D metabolites on adenoma recurrence. Further study is necessary to characterize the differences between circulating vitamin D metabolite measurements compared to cellular level activity in relation to cancer risk.

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.

Associations of vitamin D pathway genes with circulating 25-hydroxyvitamin-D, 1,25-dihydroxyvitamin-D, and prostate cancer: a nested case-control study

PURPOSE

Vitamin D pathway single nucleotide polymorphisms (SNPs) are potentially useful proxies for investigating whether circulating vitamin D metabolites [total 25-hydroxyvitamin-D, 25(OH)D; 1,25-dihydroxyvitamin, 1,25(OH)2D] are causally related to prostate cancer. We investigated associations of sixteen SNPs across seven genes with prostate-specific antigen-detected prostate cancer.

METHODS

In a nested case-control study (within the ProtecT trial), we estimated odds ratios and 95 % confidence intervals (CIs) quantifying associations between SNPs and prostate cancer. Subgroup analyses investigated whether associations were stronger in men who had high/low sun exposure [a proxy for 25(OH)D]. We quantified associations of SNPs with stage (T1-T2/T3-T4) and grade (<7/≥7). Multiple variant scores included SNPs encoding proteins involved in 25(OH)D synthesis and metabolism.

RESULTS

We included 1,275 prostate cancer cases (141 locally advanced, 385 high grades) and 2,062 healthy controls. Vitamin D-binding protein SNPs were associated with prostate cancer (rs4588-A: OR 1.20, CI 1.01, 1.41, p = 0.04; rs7041-T: OR 1.19, CI 1.02, 1.38, p = 0.03). Low 25(OH)D metabolism score was associated with high (vs low) grade (OR 0.76, CI 0.63, 0.93, p = 0.01); there was a similar association of its component variants: rs6013897-A in CYP24A1 (OR 0.78, CI 0.60, 1.01, p = 0.06) and rs10877012-T in CYP27B1 (OR 0.80, CI 0.63, 1.02, p = 0.07). There was no evidence that associations differed by level of sun exposure.

CONCLUSION

We found some evidence that vitamin D pathway SNPs were associated with prostate cancer risk and grade, but not stage. There was no evidence of an association in men with deficient vitamin D (measured by having low sun exposure).

Vitamin D-related gene polymorphisms, plasma 25-hydroxyvitamin D, and breast cancer risk

PURPOSE

Studies of vitamin D-pathway genetic variants in relation to cancer risk have been inconsistent. We examined the associations between vitamin D-related genetic polymorphisms, plasma 25-hydroxyvitamin D [25(OH)D], and breast cancer risk.

METHODS

In a population-based case-control study of 967 incident breast cancer cases and 993 controls, we genotyped 25 polymorphisms encoding the vitamin D receptor (VDR) gene, 1α-hydroxylase (CYP27B1), 24-hydroxylase (CYP24A1), and vitamin D-binding protein (GC) and measured plasma 25(OH)D. We used multivariable logistic regression to estimate adjusted odds ratios (ORs) and 95 % confidence intervals (CIs).

RESULTS

Among CYP24A1 polymorphisms, rs6068816 was associated with a 72 % reduction in breast cancer risk (TT vs. CC, OR 0.28, 95 % CI 0.10-0.76; p trend = 0.01), but for rs13038432, the 46 % decrease included the null value (GG vs. AA, OR 0.54, 95 % CI 0.17-1.67; p trend = 0.03). Increased risk that included the null value was noted for CYP24A1 rs3787557 (CC vs. TT, OR 1.34, 95 % CI 0.92-1.89). The VDR polymorphism, TaqI (rs731236), was associated with a 26 % risk reduction (TT vs. CC, OR 0.74, 95 % CI 0.56-0.98; p trend = 0.01). For other polymorphisms, ORs were weak and included the null value. The inverse association for plasma 25(OH)D with breast cancer was more pronounced (OR 0.43, 95 % CI 0.27-0.68) among women with the common allele for CYP24A1, rs927650 (p for interaction on a multiplicative scale = 0.01).

CONCLUSION

Breast cancer risk may be associated with specific vitamin D-related polymorphisms, particularly CYP24A1. Genetic variation in the vitamin D pathway should be considered when designing potential intervention strategies with vitamin D supplementation.

Common genetic variations in the vitamin D pathway in relation to blood pressure

BACKGROUND

Vitamin D is involved in blood pressure (BP) regulation. Genetic variations may influence the effect of vitamin D on BP, but data from epidemiologic studies remain inconsistent.

METHODS

We conducted a comprehensive genetic association study in the Women's Genome Health Study (WGHS) with genome-wide genotype data among 23,294 women of European ancestry and in the International Consortium of Blood Pressure (ICBP) with genome-wide meta-analysis results from 69,395 men and women of European ancestry.

RESULTS

First, we found none of 5 selected vitamin D-related candidate single nucleotide polymorphisms (SNPs) was associated with systolic BP (SBP) or diastolic BP (DBP). Second, in 61 candidate SNPs involved in vitamin D metabolism and signaling, rs1507023 (in RBFOX1) and rs2296241 (in CYP24A1) showed significant associations with SBP, DBP, mean arterial pressure, or pulse pressure in the WGHS before, but not after, multiple testing corrections. Nominally significant associations in the ICBP were also not significant after corrections. Third, among 24 candidate genes across vitamin D pathway, associations with BP traits that meet gene-wide significance level were found for NCOA3 (rs2235734), RXRA (rs875444), DHCR7 (rs1790370), VDR (rs2544037), and NCOR2 (rs1243733, rs1147289) in the WGHS and NCOR1, TP53BP1, and TYRP1 in the ICBP. However, none of these associations reached significance threshold in both studies.

CONCLUSIONS

Our study did not replicate previously observed associations of vitamin D-related SNPs with BP. There was suggestive evidence for associations in other vitamin D pathway genes; however, these associations either did not reach the significance threshold or were not replicated.

Vitamin D pathway gene variants and HCV-2/3 therapy outcomes

BACKGROUND

The combination of ribavirin and pegylated interferon-α is considered the standard of care for HCV-2/3 genotypes. The immune system plays a key role in the achievement of a sustained virological response (SVR). Vitamin D seems to influence antiviral response in chronic hepatitis C and its pathway is controlled by polymorphic genes such as CYP27B1, CYP24A1 and VDR. In this study, we have investigated the correlation among the treatment outcomes and single nucleotide polymorphisms (SNPs) in the above-mentioned genes and IL28B genes.

METHODS

A total of 112 HCV-2/3 patients treated with interferon plus ribavirin were retrospectively studied; allelic discrimination was performed by real-time PCR.

RESULTS

CYP24A1rs2585428, IL28Brs12979860 and rs8099917 SNPs affected treatment failure and body mass index (BMI), Metavir score, IL28Brs8099917TT and CYP24A1rs2585428GG were the only factors able to predict it. SVR was predicted by Metavir score, HCV RNA at baseline and early virological response (EVR). IL28Brs12979860 SNP and HCV RNA were also related to rapid virological response. EVR was predicted by BMI, Metavir score and CYP24A1rs2585428 SNP. IL28Brs8099917TT and FokITT were relapse prediction factors.

CONCLUSIONS

In addition to non-genetic factors, SNPs in the vitamin D pathway seem to have a role in HCV-2/3 therapy outcomes. This study reveals the likely usefulness of pharmacogenetic-based ribavirin and interferon therapy to help identify patients for whom therapy could be successful or not, also considering new future expensive therapy options. To date, no similar data were published on these viral genotypes, but further studies in different and bigger cohorts are needed.

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.

Role of Vitamin D Metabolism and Activity on Carcinogenesis

The vitamin D endocrine system regulates a broad variety of independent biological processes, and its deficiency is associated with rickets, bone diseases, diabetes, cardiovascular diseases, and tuberculosis. Cellular and molecular studies have also shown that it is implicated in the suppression of cancer cell invasion, angiogenesis, and metastasis. Sunlight exposure and consequent increased circulating levels of vitamin D are associated with reduced occurrence and a reduced mortality in different histological types of cancer, including those resident in the skin, prostate, breast, colon, ovary, kidney, and bladder. The vitamin D receptor (VDR) as a steroid hormone superfamily of nuclear receptors is highly expressed in epithelial cells at risk for carcinogenesis, providing a direct molecular link by which vitamin D status impacts on carcinogenesis. Because VDR expression is retained in many human tumors, vitamin D status may be an important modulator of cancer progression in persons living with cancer. The aim of this review is to highlight the relationship between vitamin D, VDR, and cancer, summarizing several mechanisms proposed to explain the potential protective effect of vitamin D against the development and progression of cancer.

Associations of circulating 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and vitamin D pathway genes with prostate-specific antigen progression in men with localized prostate cancer undergoing active monitoring

Current diagnostic tests cannot differentiate the majority of prostate cancers with a low likelihood of progression from the minority with more aggressive potential. We examined whether the measures of vitamin D were associated with prostate-specific antigen (PSA) doubling time in men undergoing active monitoring. We examined the associations of circulating 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and vitamin D pathway polymorphisms with PSA doubling time in 490 men undergoing active monitoring for localized prostate cancer within a UK population-based cohort study [mean follow-up 4.4 years (range: 0.3-7.6)]. Repeat PSA measurements were analyzed using multilevel models. There was no evidence that circulating 25(OH)D levels, 1,25(OH)2D levels, or vitamin D pathway polymorphisms were associated with postdiagnosis PSA doubling time. Stratifying the results by prostate cancer grade at diagnosis (high grade or low grade) did not alter the results. We found no evidence that either circulating 25(OH)D, 1,25(OH)2D, or vitamin D pathway polymorphisms were associated with PSA doubling time in men undergoing active monitoring for localized prostate cancer. Future studies should examine the associations of variation in vitamin D with clinical outcomes (metastases and death).

Circulating levels of 25-hydroxyvitamin D and prostate cancer prognosis

OBJECTIVES

Ecological, in vitro, and in vivo studies demonstrate a link between vitamin D and prostate tumor growth and aggressiveness. The goal of this study was to investigate whether plasma concentration of vitamin D is associated with survivorship and disease progression in men diagnosed with prostate cancer.

MATERIALS AND METHODS

We conducted a population-based cohort study of 1476 prostate cancer patients to assess disease recurrence/progression and prostate cancer-specific mortality (PCSM) risks associated with serum levels of 25(OH) vitamin D [25(OH)D].

RESULTS

There were 325 recurrence/progression and 95 PCSM events during an average of 10.8 years of follow-up. Serum levels of 25(OH)D were not associated with risk of recurrence/progression or mortality. Clinically deficient vitamin D levels were associated with an increased risk of death from other causes.

CONCLUSIONS

We did not find evidence that serum vitamin D levels measured after diagnosis affect prostate cancer prognosis. Lower levels of vitamin D were associated with risk of non-prostate cancer mortality.

Role of calcium, vitamin D, and the extrarenal vitamin D hydroxylases in carcinogenesis

Vitamin D deficiency and low calcium intake are considered risk factors for several cancers. Vitamin D, synthesized in the skin or ingested through the diet, is transformed through two hydroxylation steps to the active metabolite, 1α,25-dihydroxyvitamin D3 (1,25-D3). 25-hydroxylases in the liver are responsible for the first hydroxylation step. The ultimate activation is performed by the renal 25-hydroxyvitamin D 1α-hydroxylase (CYP27B1), while the 1,25-dihydroxyvitamin D 24-hydroxylase (CYP24A1) in the kidneys degrades the active metabolite. These two renal vitamin D hydroxylases control the endocrine serum 1,25-D3 levels, and are responsible for maintaining mineral homeostasis. In addition, the active vitamin D hormone 1,25-D3 regulates cellular proliferation, differentiation, and apoptosis in multiple tissues in a paracrine/autocrine manner. Interestingly, it is the low serum level of the precursor 25- hydroxyvitamin D3 (25-D3) that predisposes to numerous cancers and other chronic diseases, and not the serum concentration of the active vitamin D hormone. The extra-renal autocrine/paracrine vitamin D system is able to synthesize and degrade locally the active 1,25- D3 necessary to maintain normal cell growth and to counteract mitogenic stimuli. Thus, vitamin D hydroxylases play a prominent role in this process. The present review describes the role of the vitamin D hydroxylases in cancer pathogenesis and the cross-talk between the extra-renal autocrine/paracrine vitamin D system and calcium in cancer prevention.

Genetic sequence variants in vitamin D metabolism pathway genes, serum vitamin D level and outcome in head and neck cancer patients

Although some studies have reported associations between serum vitamin D level and prognosis in several cancers, others have found associations between genetic sequence variants (GSVs) in the vitamin D metabolism pathway genes and outcomes in various cancers including head and neck cancer (HNC). We comprehensively evaluated the association and interaction of GSVs in vitamin D metabolism pathway genes and their regulatory effects on circulatory serum vitamin D level in HNC outcome. We systemically evaluated the association of 89 tagging and candidate-based GSVs in six major vitamin D metabolism pathway genes (VDR, GC, CYP24A1, CYP27A1, CYP27B1 and CYP2R1) and the circulating serum vitamin D level with overall survival (OS) and second primary cancer (SPC) in 522 Stages I-II radiation-treated patients with HNC. For OS: median follow-up time was 8 years; for SPC, 4.4 years. The most common subsite was the larynx (84%). Three hundred and twelve patients were alive at the end of follow-up for OS. SPCs were diagnosed in 108 patients and were primarily of lung (46%). Serum vitamin D levels were significantly lower in patients carrying the minor alleles of GC:rs4588 and CYP2R1:rs10500804. CYP24A1:rs2296241 was significantly associated with OS and CYP2R1:rs1993116 was with SPC. These two GSVs remained significantly associated after adjusting for serum vitamin D level and important clinical factors. GSVs in the vitamin D metabolism pathway genes were associated with disease outcomes in HNC patients; however, these GSVs are different from those affecting serum vitamin D levels.

Single nucleotide polymorphisms and risk of recurrence of renal-cell carcinoma: a cohort study

BACKGROUND

Germline genetic polymorphisms might affect the risk of recurrence in patients with localised renal-cell carcinoma. We investigated the association between genetic polymorphisms and recurrence of renal-cell carcinoma.

METHODS

We analysed germline DNA samples extracted from patients with localised renal-cell carcinoma treated at the Dana-Farber/Harvard Cancer Center (Boston, MA, USA). We selected a discovery cohort from a prospective database at the Dana-Farber/Harvard Cancer Center and selected a validation cohort from department records at the Brigham and Women's Hospital (Boston, MA, USA). We validated the findings from the discovery cohort in the validation cohort. We genotyped 70 genes involved in the pathogenesis of renal-cell carcinoma (including the VHL/HIF/VEGF and PI3K/AKT/mTOR pathways, and genes involved in immune regulation and metabolism) for single nucleotide polymorphisms. We assessed the association between genotype and recurrence-free survival, adjusted for baseline characteristics, with the Cox proportional hazards model, the Kaplan-Meier method, and the log-rank test. We used a false discovery rate q value to adjust for multiple comparisons.

FINDINGS

We included 554 patients (403 in the discovery cohort and 151 in the validation cohort). We successfully genotyped 290 single nucleotide polymorphisms in the discovery cohort, but excluded five because they did not have a variant group for comparison. The polymorphism rs11762213, which causes a synonymous aminoacid change in MET (144G→A, located in exon 2), was associated with recurrence-free survival. Patients with one or two copies of the minor (risk) allele had an increased risk of recurrence or death (hazard ratio [HR] 1·86, 95% CI 1·17-2·95; p=0·0084) in multivariate analysis. Median recurrence-free survival for carriers of the risk allele was 19 months (95% CI 9-not reached) versus 50 months (95% CI 37-75) for patients without the risk allele. In the validation cohort the HR was 2·45 (95% CI 1·01-5·95; p=0·048).

INTERPRETATION

Patients with localised renal-cell carcinoma and the MET polymorphism rs11762213 might have an increased risk of recurrence after nephrectomy. If these results are further validated in a similar population, they could be incorporated into future prognostic instruments, potentially aiding the design of adjuvant clinical trials of MET inhibitors and management of renal-cell carcinoma.

FUNDING

Conquer Cancer Foundation and American Society of Clinical Oncology (Career Development Award); The Trust Family Research Fund for Kidney Cancer; US National Institutes of Health, National Cancer Institute Kidney Cancer Specialized Program of Research Excellence.

Regulation of CYP3A4 and CYP3A5 expression and modulation of "intracrine" metabolism of androgens in prostate cells by liganded vitamin D receptor

We investigated the capacity for vitamin D receptor (VDR) to modulate the expression of CYP3A4 and other genes that may facilitate the oxidative inactivation of androgens such as testosterone and androstanediol within prostate cells. We report that exposure to the active hormonal form of vitamin D markedly increased gene expression of CYP3A4 and CYP3A5 and ultimately achieved levels of intracellular CYP3A enzyme activity within LNCaP prostate cancer cells that were comparable to that observed for Caco2 cells, an established model of CYP3A induction, and resulted in the increased turnover of testosterone to its inactive 6β-OH metabolite. We demonstrate that VDR directs CYP3A4 and CYP3A5 expression through binding to distinct regulatory motifs located within the 5' promoter regions of both genes. The current data highlight the potential application of VDR-based treatment regimes as a means to limit the bioavailability of growth-promoting androgens within the tumor microenvironment.

Current progress in using vitamin D and its analogs for cancer prevention and treatment

Vitamin D has long been known for its physiological role in mineral homeostasis through its actions on the intestines, kidneys, parathyroid glands and bone. However, recent observations of antiproliferative, prodifferentiating and antiangiogenic effects elicited by the bioactive form of vitamin D (1,25[OH](2)D(3)) in a broad range of cancers is less well understood. Here, we review the increasing epidemiological and experimental evidence that supports the development of 1,25(OH)(2)D(3) and vitamin D analogs as preventative and therapeutic anticancer agents. Furthermore, this review summarizes the preclinical and clinical studies of vitamin D and its analogs over the past decade, indicating the current problems of dose-limiting toxicity from hypercalcemia and large interpatient variability in pharmacokinetics. A better understanding of how genetic variants influence vitamin D status should not only improve cancer risk predictions, but also promote the development of vitamin D analogs with more specific actions to improve therapeutic outcomes.