Vitamin D receptor gene polymorphisms and colorectal cancer risk: A systematic meta-analysis

Common variants of vitamin D receptor gene polymorphisms and risk of gastric cancer: A meta-analysis

BACKGROUND

While earlier studies have suggested that variations in the vitamin D receptor (VDR) gene could influence the susceptibility to gastric cancer (GC), the results have shown inconsistency. This meta-analysis aimed to examine the association of 5 common polymorphisms in VDR, including Taq1 rs731236 (T > C), FokI rs2228570 (C > T), Cdx2 rs11568820 (G > A), BsmI rs1544410 (G > A), and ApaI rs7975232 (G > T) with the risk of GC.

METHODS

A comprehensive search was carried out in PubMed, Web of Science, and Scopus to identify relevant studies published until January 2024. Odds ratios (ORs) with 95% confidence intervals (CIs) were utilized to assess the magnitude of associations.

RESULTS

Nine studies, with 2837 participants (1215 GC cases and 1622 healthy controls), were eligible. The FokI rs2228570 polymorphism showed a significant correlation with heightened susceptibility to GC under the recessive model (OR = 1.52; 95% CI: 1.06-2.19) and homozygote comparison (TT vs CC; OR = 1.59; 95% CI: 1.09-2.31). Taq1 rs731236 was also linked to an elevated risk of GC under the same models (recessive OR = 1.65; 95% CI: 1.14-2.39; homozygote OR = 1.68; 95% CI: 1.11-2.54). In the sensitivity analysis, when studies not adhering to Hardy-Weinberg equilibrium were excluded, the relationship between FokI rs2228570 polymorphism and GC disappeared, while the association for Taq1 rs731236 remained consistent. No significant association was identified for BsmI rs1544410, ApaI rs7975232, and Cdx2 rs11568820.

CONCLUSION

This study revealed that FokI rs2228570 and Taq1 rs731236 polymorphisms of VDR might be linked to the odds of GC.

Role of Vitamin D Receptor (BsmI-VDR) and Insulin Receptor (NsiI-A/G) Gene Polymorphisms in Colorectal Adenoma Susceptibility

Vitamin D deficiency and type 2 diabetes mellitus are risk factors for colorectal cancer, suggesting a role for vitamin D receptor (VDR) and insulin receptor (INSR) gene polymorphisms. We investigated the prevalence of the VDR-BsmI (rs1544410) and NsiI A/G-INSR (rs2059806) polymorphisms and their associations with colorectal adenoma (CRA) in a Romanian population. A case-control study was conducted with 110 participants (67 with CRA and 43 controls) who underwent colonoscopy. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to determine the genotype and allele frequencies of the two polymorphisms. Regarding rs1544410 and CRA patients, genotype distribution was 35% B/B, 47% B/b, and 19% b/b. In the controls, the distribution was 21% B/B, 45% B/b, and 34% b/b. For rs2059806, 12% of CRA patients had A/A, 30% A/G, and 58% G/G, while 8% of the controls had A/A, 40% A/G, and 52% G/G. The recessive model showed an odds ratio of 2.84 (95% CI: 1.04-7.72, p = 0.033) for the b/b genotype. CRA patients with b/b or G/G genotypes were diagnosed at a younger age. The b allele of the rs1544410 was a risk factor for CRA. Patients with the b/b and G/G genotypes were diagnosed earlier.

Is vitamin D receptor (VDR) polymorphism associated with head and neck cancer risk? A systematic review and meta-analysis

BACKGROUND

Head and neck cancer encompasses neoplasms affecting the oral cavity, pharynx, larynx, and thyroid. Identifying factors that modulate the carcinogenesis process can aid in identifying subgroups at higher risk of developing the disease, enabling implementation of prevention programs. Vitamin D receptor polymorphisms can affect the carcinogenesis of various tumors by altering vitamin D metabolism and cellular response.

METHODS

To elucidate the role of vitamin D receptor polymorphisms in head and neck cancer, a systematic review was performed, searching the Embase, PubMed, Scopus, and Lilacs databases. A total of 19 articles met the inclusion criteria. The frequency of vitamin D receptors polymorphism alleles (FokI, ApaI, BsmI, TaqI, Cdx2, rs2107301, rs2238135) was recorded and pooled to calculate the odds ratio in a meta-analysis using the Review Manager software.

RESULTS

Subgroup analysis demonstrated significant associations in the anatomical site of cancer (oral cancer in ApaI and BsmI, and unspecified subsites of head and neck cancer in TaqI), genotyping method (FokI and BsmI), and continent of the study (ApaI, FokI, and BsmI).

CONCLUSION

Our findings were heterogeneous, as with other evidence available in the literature. Therefore, more clinical studies with larger sample sizes are needed to obtain more accurate results on the relationship between vitamin D receptor polymorphism and head and neck cancer.

Vitamin D Supplementation and Adherence to World Cancer Research Fund (WCRF) Diet Recommendations for Colorectal Cancer Prevention: A Nested Prospective Cohort Study of a Phase II Randomized Trial

Vitamin D and a healthy diet, based on World Cancer Research Fund (WCRF) recommendations, are considered key elements for colorectal cancer (CRC) prevention. In a CRC case-control study, we observed that CRC cases were often significantly Vitamin D deficient while subjects following WCRF recommendations significantly decreased their risk of developing CRC. We conducted a randomized phase-II trial (EudraCT number-2015-000467-14) where 74 CRC patients showed differences in response to Vitamin D supplementation, 2000 IU in average per day, according to gender and microbiota. The aim of this nested study is to correlate Vitamin D (supplementation, serum level and receptor polymorphisms), circulating biomarkers, and events (polyp/adenoma, CRC relapse and other cancers) in concomitant to WCRF recommendation adherence. Vitamin D supplementation did not modulate circulating biomarkers or follow-up events. FokI and TaqI VDR were associated with 25-hydroxyvitamin D (25OHD) levels. Patients following the WCRF recommendations had significantly lower leptin, significantly lower IL-6 (only in females), and significantly lower risk of events (HR = 0.41, 95%CI: 0.18-0.92; p = 0.03; median follow-up 2.6 years). Interestingly, no WCRF adherents had significantly more events if they were in the placebo (p < 0.0001), whereas no influence of WCRF was observed in the Vitamin D arm. While one-year Vitamin D supplementation might be too short to show significant preventive activity, a healthy diet and lifestyle should be the first step for preventive programs.

Association between Single Nucleotide Polymorphisms Related to Vitamin D Metabolism and the Risk of Developing Asthma

Asthma is a chronic non-communicable disease that affects all age groups. The main challenge this condition poses is its heterogeneity. The role of vitamin D in asthma has aroused great interest, correlating low vitamin D levels and polymorphisms in the genes involved in its metabolic pathway with the risk of asthma. The aim of this study was to evaluate the influence of 13 single nucleotide polymorphisms (SNPs) related to the vitamin D metabolism on the susceptibility to asthma. An observational case-control study was performed, including 221 patients with asthma and 442 controls of Caucasian origin from southern Spain. The SNPs CYP24A1 (rs6068816, rs4809957), CYP27B1 (rs10877012, rs4646536, rs703842, rs3782130), GC (rs7041), CYP2R1 (rs10741657) and VDR (ApaI, BsmI, FokI, Cdx2, TaqI) were analyzed by real-time PCR, using TaqMan probes. The logistic regression model adjusted for body mass index revealed that in the genotype model, carriers of the Cdx2 rs11568820-AA genotype were associated with a higher risk of developing asthma (p = 0.005; OR = 2.73; 95% CI = 1.36-5.67; AA vs. GG). This association was maintained in the recessive model (p = 0.004). The haplotype analysis revealed an association between the ACTATGG haplotype and higher risk of asthma for the rs1544410, rs7975232, rs731236, rs4646536, rs703842, rs3782130 and rs10877012 genetic polymorphisms (p = 0.039). The other SNPs showed no effect on risk of developing asthma. The Cdx2 polymorphism was significantly associated with the susceptibility of asthma and could substantially act as a predictive biomarker of the disease.

Association of vitamin D receptor polymorphisms with colorectal cancer susceptibility: A systematic meta-analysis

BACKGROUND

Recent studies have reported an association between vitamin D receptor (VDR) polymorphisms and colorectal cancer (CRC) risk; however, the results are controversial. This meta-analysis was performed to investigate whether the Cdx-2, Tru9I, FokI, BsmI, TaqI, and ApaI polymorphisms were correlated with CRC susceptibility.

METHODS

All potential studies were retrieved by searching the PubMed, EMBASE, and Cochrane Library databases through October 2, 2021. Odds ratios (ORs) with 95% confidence intervals were used to evaluate the correlation between VDR gene Cdx-2, Tru9I, FokI, BsmI, TaqI, and ApaI polymorphisms and CRC risk.

RESULTS

In this meta-analysis, the BsmI variant was significantly correlated with a lower risk of CRC, especially in Caucasian population (B vs b: OR 0.94, 95%CI 0.90-0.99; BB vs bb: OR 0.88; 95%CI 0.79-0.97; BB vs Bb/bb: BB vs Bb/bb: OR 0.89; 95%CI 0.81-0.98). A statistically significant result from the FokI polymorphism was observed in colon cancer rather than rectal cancer (Ff vs FF: OR 0.86, 95%CI 0.84-0.93; ff/Ff vs FF: OR 0.88, 95%CI 0.79-0.98; ff vs Ff/FF: OR 0.90, 95%CI 0.82-0.99). Similarly, Cdx-2 polymorphism was found to be associated with decreased CRC risk among Africans (C vs c: OR 0.50, 95%CI 0.33-0.75; CC vs cc: OR 0.09, 95%CI 0.01-0.77; Cc vs cc: OR 0.49, 95%CI 0.30-0.81; CC/Cc vs cc: OR 0.45, 95%CI 0.28-0.74,).

CONCLUSION

Our findings indicate that VDR polymorphisms are significantly associated with CRC risk.

Investigation of Microbial Translocation, TLR and VDR Gene Polymorphisms, and Recurrence Risk in Stage III Colorectal Cancer Patients

Gut microbial dysbiosis and microbial passage into the peripheral blood leads to colorectal cancer (CRC) and disease progression. Toll-like (TLR) and vitamin D (VDR) receptors play important role in the immune modulation and polymorphisms that may increase CRC risk and death rates. The aim of the current study was to demonstrate the prognostic value of microbial DNA fragments in the blood of stage III CRC patients and correlate such microbial detection to TLR/VDR polymorphisms. Peripheral blood was collected from 132 patients for the detection of microbial DNA fragments, and TLR/VDR gene polymorphisms. In the detection of various microbial DNA fragments, TLR and VDR polymorphisms was significantly higher compared to healthy group. Homozygous individuals of either TLR or VDR polymorphisms had significantly higher detection rates of microbial DNA fragments. Mutational and MSI status were significantly correlated with TLR9 and VDR polymorphisms. Significantly shorter disease-free survival was associated with patients with BRAF mutated tumors and ApaI polymorphisms, whereas shorter overall survival was associated with the detection of C. albicans. The detection of B. fragilis, as demonstrated by the multivariate analysis, is an independent poor prognostic factor for shorter disease-free survival. TLR/VDR genetic variants were significantly correlated with the detection of microbial fragments in the blood, and this in turn is significantly associated with tumorigenesis and disease progression.

Vitamin D and colorectal cancer - A practical review of the literature

Colorectal cancer (CRC) is the third leading cause of cancer-related mortality in the United States and the second cause worldwide. Its incidence rates have been decreasing in the overall population in the US in the past few decades, but with increasing rates in the population younger than 50 years old. Environmental factors are supposed to be involved in the development of the disease, with strong evidence favoring an influence of the diet and lifestyle. A diet high in red meat and calories, and low in fiber, fruits and vegetables increases the risk of CRC, as well as physical inactivity. The influence of low calcium intake and low levels of vitamin D on the risk of the disease and on the clinical outcomes of CRC patients has also been investigated. Hypovitaminosis D has been highly prevalent worldwide and associated with several chronic diseases, including malignancies. Vitamin D is a steroid hormone with the main function of regulating bone metabolism, but with many other physiological functions, such as anti-inflammatory, immunomodulatory, and antiangiogenic effects, potentially acting as a carcinogenesis inhibitor. In this review, we aim to describe the relation of vitamin D with malignant diseases, mainly CRC, as well as to highlight the results of the studies which addressed the potential role of vitamin D in the development and progression of the disease. In addition, we will present the results of the pivotal randomized clinical trials that evaluated the impact of vitamin D supplementation on the clinical outcomes of patients with CRC.

Association of Vitamin D Gene Polymorphisms With HCV Infection Outcome

Background: Vitamin D derivatives and their receptor (VDR) are immune-response modulators in many diseases including malignancies, metabolic conditions, and infections. We hypothesized that one or more variants of VDR single nucleotide polymorphisms (SNPs) are associated with hepatocellular carcinoma (HCC) in hepatitis C virus (HCV) cirrhotic patients. Materials and Methods: A total of 861 subjects were recruited and classified as spontaneous viral clearance (SVC, n = 127), chronic hepatic cirrhosis (CHC, n = 392), and HCC (n = 342). Standard routine laboratory tests were performed and clinical features noted. All individuals were genotyped for seven SNPs spanning the VDR using real-time PCR. Results: Genotype frequencies of SNPs rs7970376, rs11568820, rs4516035, rs2228570 (Fok1), rs1544410 (Bsm-1), and rs731236 (Taq1), but not rs739837, were variously altered in CHC and HCC compared with SVC, and in HCC compared to CHC (all p < 0.001). The most powerful was rs7970376, which brought an OR (95% CI) of 7.14 (4.64-10.98) for HCC compared to SVC (p = 0.001). The carriage of the AGTAC haplotype of five SNPs were linked to CHC compared to SVC at OR 2.88 [95% CI 1.2-6.9] (p = 0.017) and with HCC compared to CHC at OR 1.54 [95% CI = 1.04-2.27 (p = 0.031). Conclusion: SNPs in VDR may have a potential role in the outcomes of patients with HCV infection. VDR SNPs; rs7970376, rs11568820, rs4516035, rs2228570 (Fok1), rs1544410 (Bsm-1), and rs731236 (Taq1) could be used as molecular markers to predict the risk of HCC.

Serum 25-Hydroxyvitamin D and Subsequent Cancer Incidence and Mortality: A Population-Based Retrospective Cohort Study

OBJECTIVE

To determine the relationship between 25-hydroxyvitamin D (25[OH]D) values and subsequent cancer incidence and mortality.

PATIENTS AND METHODS

We identified all adult patients living in Olmsted County, Minnesota, between January 1, 2005, and December 31, 2011, who had at least 1 25(OH)D measurement and no prior diagnosis of cancer. Cancer outcomes were retrieved starting 30 days after 25(OH)D measurement and until patients' final clinical visit as an Olmsted County resident; December 31, 2014; or death. Cox proportional hazards regression was used to analyze data.

RESULTS

A total of 8700 individuals had a 25(OH)D measurement and no history of cancer, with a mean ± SD 25(OH)D value of 29.7±12.8 ng/mL (to convert to nmol/L, multiply by 2.496). The mean ± SD age was 51.5±16.4 years, and most were women (78.1%; n=6796) and White (85.7%; n=7460). A total of 761 individuals developed cancer (skin cancer, n=360; nonskin cancer, n=401) during a median follow-up of 4.6 (interquartile range, 3.4-6.1) years. Compared with participants with 25(OH)D values of 20 to 50 ng/mL (reference group), those with 25(OH)D values less than 12 ng/mL had a greater nonskin cancer incidence (hazard ratio [HR], 1.56; 95% CI, 1.03 to 2.36; P=.04) after adjustment. There was no association between 25(OH)D values and total cancer or skin cancer incidence. Compared with individuals from the reference group, 25(OH)D levels less than 12 ng/mL (HR, 2.35; 95% CI, 1.01 to 5.48; P=.047) and 12 to 19 ng/mL (HR, 2.10; 95% CI, 1.05 to 4.22; P=.04) were associated with increased cancer mortality.

CONCLUSION

Low 25(OH)D levels were associated with increased risk for incident nonskin cancer and cancer-related mortality.

Interactions Between Vitamin D and Calcium Intake, Vitamin D Receptor Genetic Polymorphisms, and Colorectal Cancer Risk

BACKGROUND

Vitamin D has anticarcinogenic properties and acts through vitamin D receptor (VDR) to carry out its functions.

AIMS

This study explored the independent and combined effects of dietary vitamin D and calcium, and VDR genetic polymorphisms on colorectal cancer risk in a Chinese population.

METHODS

This ongoing case-control study recruited 488 cases with histologically confirmed colorectal cancer and 496 sex- and age-matched controls. Vitamin D and calcium intakes were assessed by a validated food frequency questionnaire, and VDR genotype was conducted for Fok I (rs2228570), Bsm I (rs1544410), Apa I (rs7975232), and Taq I (rs731236). Unconditional logistic regression was used to calculate odds ratio and 95% confidence interval after adjusting for various confounders.

RESULTS

No significant association was found between Fok I, Bsm I, Apa I, Taq I, and colorectal cancer risk. Higher intakes of dietary vitamin D and calcium were associated with 47% and 50% reduction in colorectal cancer risk. Significant interaction was observed between dietary vitamin D intake and Apa I polymorphisms in relation to colorectal cancer risk (P_interaction = 0.006). Subjects with higher dietary vitamin D intake and mutant Apa I A allele had a substantially decreased risk of colorectal cancer compared to Apa I aa carriers with lower vitamin D intake.

CONCLUSIONS

Our study supports that Apa I may interact with dietary vitamin D intake on colorectal cancer risk. However, no interactions were found between dietary vitamin D or calcium intakes and Fok I, Bsm I, and Taq I in relation to colorectal cancer risk.

Vitamin D receptor gene polymorphism and hepatocellular carcinoma in chronic hepatitis C patients

Background

Hepatocellular carcinoma (HCC) is a prevalent malignancy worldwide. Vitamin D receptor (VDR) gene polymorphisms were linked to different cancers. This study was carried out to assess the possible relation between VDR gene polymorphism and the occurrence of HCC in chronic hepatitis C patients. This study included 102 subjects classified into three groups. Group A included 34 healthy subjects as control. Group B included 34 chronic hepatitis C patients with HCC. Group C included 34 chronic hepatitis C patients without HCC. Estimation of Apa-1 VDR gene polymorphism was performed by restriction fragment length polymorphism-Polymerase chain reaction (RFLP-PCR).

Results

In HCC group, C allele was more frequent than A allele (80.88% and 19.12%), respectively. In chronic hepatitis group, C allele was more frequent than A allele (64.71% and 35.29%), respectively. In control group, A allele was more frequent than C allele (73.53% and 26.47%), respectively. Genotype CC + CA was dominant in HCC group (91.18%) and chronic hepatitis group (79.41%). In the control group, the dominant genotype was AA (58.82%). Moreover, there was a significant relation between Apa-1 VDR genotype CC and tumor size.

Conclusions

There is an association between VDR Apa-1 polymorphism and the occurrence of HCC in chronic hepatitis C patients.

The Role of Vitamin D Receptor Gene Polymorphisms in Colorectal Cancer Risk

Vitamin D deficiency has been associated with increased colorectal cancer (CRC) incidence risk and mortality. Vitamin D mediates its action through the binding of the vitamin D receptor (VDR), and polymorphisms of the VDR might explain these inverse associations. The aim of the study was the investigation of the relevance of rs731236; Thermus aquaticus I (TaqI), rs7975232; Acetobacter pasteurianus sub. pasteurianus I (ApaI), rs2228570; Flavobacterium okeanokoites I (FokI) and rs1544410, Bacillus stearothermophilus I (BsmI) polymorphisms of the VDR gene to colorectal carcinogenesis (CRC) and progression. Peripheral blood was obtained from 397 patients with early operable stage II/III (n = 202) and stage IV (n = 195) CRC. Moreover, samples from 100 healthy donors and 40 patients with adenomatous polyps were also included as control groups. Genotyping in the samples from patients and controls was performed using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP). A significant association was revealed between all four polymorphisms and cancer. Individuals with homozygous mutant (tt, aa, ff or bb) genotypes were more susceptible to the disease (p < 0.001). All of the mutant genotypes detected were also significantly associated with stage IV (p < 0.001), leading to significantly decreased survival (p < 0.001). Moreover, all four polymorphisms were significantly associated with KRAS (Kirsten ras oncogene) mutations and Toll-like receptor (TLR2, TLR4 and TLR9) genetic variants. In multivariate analysis, tt, aa and ff genotypes emerged as independent factors associated with decreased overall survival (OS) (p = 0.001, p < 0.001 and p = 0.001, respectively). The detection of higher frequencies of the VDR polymorphisms in CRC patients highlights the role of these polymorphisms in cancer development and progression.

MicroRNA-binding site polymorphisms and risk of colorectal cancer: A systematic review and meta-analysis

Genetic variations in miRNAs binding site might participate in cancer risk. This study aimed to systematically review the association between miRNA-binding site polymorphisms and colorectal cancer (CRC). Electronic literature search was carried out on PubMed, Web of Science (WOS), Scopus, and Embase. All types of observational studies till 30 November 2018 were included. Overall 85 studies (21 SNPs) from two systematic searches were included analysis. The results showed that in the Middle East population, the minor allele of rs731236 was associated with decreased risk of CRC (heterozygote model: 0.76 [0.61-0.95]). The minor allele of rs3025039 was related to increased risk of CRC in East Asian population (allelic model: 1.25 [1.01-1.54]). Results for rs3212986 were significant in overall and subgroup analysis (P < .05). For rs1801157 in subgroup analysis the association was significant in Asian populations (including allelic model: 2.28 [1.11-4.69]). For rs712, subgroup analysis revealed a significant (allelic model: 1.41 [1.23-1.61]) and borderline (allelic model: 0.92 [0.84-1.00]) association in Chinese and Czech populations, respectively. The minor allele of rs17281995 increased risk of CRC in different genetic models (P < .05). Finally, rs5275, rs4648298, and rs61764370 did not show significant associations. In conclusion, minor allele of rs3025039, rs3212986, and rs712 polymorphisms increases the risk of CRC in the East Asian population, and heterozygote model of rs731236 polymorphism shows protective effect in the Middle East population. In Europeans, the minor allele of rs17281995 may increase the risk of CRC, while rs712 may have a protective effect. Further analysis based on population stratifications should be considered in future studies.

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

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

Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk

Colorectal cancer (CRC) is one of the leading cancers throughout the world. It represents the third most common cancer and the fourth in mortality. Most of CRC are sporadic, arise with no known high-penetrant genetic variation and with no previous family history. The etiology of sporadic CRC is considered to be multifactorial and arises from the interaction of genetic variants of low-penetrant genes and environmental risk factors. The most common well-studied genetic variation is single nucleotide polymorphisms (SNPs). SNP arises as a point mutation. If the frequency of the sequence variation reaches 1% or more in the population, it is referred to as polymorphism, but if it is lower than 1%, the allele is typically considered as a mutation. Lots of SNPs have been associated with CRC development and progression, for example, genes of TGF-β1 and CHI3L1 pathways. TGF-β1 is a pleiotropic cytokine with a dual role in cancer development and progression. TGF-β1 mediates its actions through canonical and noncanonical pathways. The most important negative regulatory protein for TGF-β1 activity is termed SMAD7. The production of TGF-β can be controlled by another protein called YKL-40. YKL-40 is a glycoprotein with an important role in cancer initiation and metastasis. YKL-40 is encoded by the CHI3L1 gene. The aim of the present review is to give a brief introduction of CRC, SNP, and examples of some SNPs that have been documented to be associated with CRC. We also discuss two important signaling pathways TGF-β1 and CHI3L1 that influence the incidence and progression of CRC.

Positive correlation between vitamin D receptor gene FokI polymorphism and colorectal cancer susceptibility in South-Khorasan of Iran

Colorectal cancer (CRC) is a global public health problem. Despite the major milestone in early diagnosis and treatment of colorectal cancer, the prevalence of CRC rates is still rising. The etiology of CRC is still unknown but we know CRC is influenced by both of environment and genetic factors. In this study, we aimed to elucidate the role of vitamin D receptor gene polymorphic regions; FokI and TaqI single nucleotide polymorphisms, in increasing the risk of colorectal cancer in Birjand population. One hundred patients with CRC and 100 healthy controls recruited to the study. Genotyping was performed by PCR-RFLP (restriction fragment length polymorphism) method technique for all individuals. There were statistically significant differences between ff genotype and f allele of FokI SNP in case and control groups. Our results manifested positive correlation between ff genotype and f allele of FokI SNP with colorectal cancer predisposition (P = 0.035, P = 0.0001 respectively) in South Khorasan population. The present study showed that FokI polymorphism but not TaqI polymorphism may contribute to CRC susceptibility. In addition, ff genotype of FokI polymorphism was associated with CRC risk.

Association between vitamin D receptor gene polymorphisms and idiopathic hypocitraturia in a Chinese Bai population

Idiopathic hypocitraturia (IH) is a risk factor for urolithiasis. IH is associated with vitamin D receptor (VDR) gene single nucleotide polymorphisms (SNPs) in a Chinese Han population. However, this association between VDR SNPs and IH has not been recapitulated in a Chinese Bai population. The aim of this study is to investigate the association between VDR SNPs and IH in a Chinese Bai population. A total of 320 participants comprising of 200 Chinese Bai patients with IH and 120 Chinese Bai control participants with normal urinary citrate level were enrolled for this study. The VDR SNPs rs7975232, rs2228570, rs731236 and rs1544410 were detected by Sanger sequencing, and the association between these SNPs and the presence of IH in the Chinese Bai population was analyzed. The prevalence of VDR SNPs rs7975232 allele A and rs2228570 genotype TT was significantly higher in patients than in controls (p < 0.0125, after Bonferroni correction). The haplotype TCGC was a protective factor in the Chinese Bai population who otherwise might suffer from IH, while the haplotype TTGA was a risk factor. VDR SNPs rs731236 and rs1544410 have a linkage disequilibrium value of 0.811. VDR SNPs rs7975232, rs2228570, and haplotypes TCGC, TTGA are associated with IH in a Chinese Bai population.

The burgeoning role of cytochrome P450-mediated vitamin D metabolites against colorectal cancer

The metabolites of vitamin D₃ (VD3) mediated by different cytochrome P450 (CYP) enzymes, play fundamental roles in many physiological processes in relation to human health. These metabolites regulate a variety of cellular signal pathways through the direct binding of activated vitamin D receptor/retinoic X receptor (VDR/RXR) heterodimeric complex to specific DNA sequences. Thus, the polymorphisms of VDR and VD3 metabolizing enzymes lead to differentiated efficiency of VD3 and further affect serum VD3 levels. Moreover, VDR activation is demonstrated to inhibit the growth of various cancers, including colorectal cancer. However, excessive intake of vitamin D may lead to hypercalcemia, which limits the application of vitamin D tremendously. In this review, we have summarized the advances in VD3 research, especially the metabolism map of VD3 and the molecular mechanisms of inhibiting growth and inducing differentiation in colorectal cancer mediated by VDR-associated cellular signal pathways. The relationship between VDR polymorphism and the risk of colorectal cancer is also illustrated. In particular, novel pathways of the activation of VD3 started by CYP11A1 and CYP3A4 are highlighted, which produce several noncalcemic and antiproliferative metabolites. At last, the hypothesis is put forward that further research of CYP-mediated VD3 metabolites may develop therapeutic agents for colorectal cancer without resulting in hypercalcemia.

Low penetrance genetic polymorphisms as potential biomarkers for colorectal cancer predisposition

Colorectal cancer is a leading form of cancer in both males and females. Early detection of individuals at risk of colorectal cancer allows proper treatment and management of the disease to be implemented, which can potentially reduce the burden of colorectal cancer incidence, morbidity and mortality. In recent years, the role of genetic susceptibility factors in mediating predisposition to colorectal cancer has become more and more apparent. Identification of high-frequency, low-penetrance genetic polymorphisms associated with the cancer has therefore emerged as an important approach which can potentially aid prediction of colorectal cancer risk. However, the overwhelming amount of genetic epidemiology data generated over the past decades has made it difficult for one to assimilate the information and determine the exact genetic polymorphisms that can potentially be used as biomarkers for colorectal cancer. This review comprehensively consolidates, based primarily on results from meta-analyses, the recent progresses in the search of colorectal cancer-associated genetic polymorphisms, and discusses the possible mechanisms involved.

Associations between VDR gene polymorphisms and colorectal cancer susceptibility: an updated meta-analysis based on 39 case-control studies

BACKGROUND

Recent studies have reported the associations between vitamin D receptor (VDR) polymorphisms and colorectal cancer (CRC), but the results were not always consistent. This meta-analysis aims to evaluate whether VDR polymorphisms are associated with CRC susceptibility.

MATERIALS AND METHODS

Studies on the associations between VDR polymorphisms and CRC were retrieved from the Web of Science, PubMed, the Chinese Biomedical Database (CBM), Chinese National Knowledge Infrastructure (CNKI) and Wanfang (Chinese) databases. The odds ratio (OR) with 95% confidence intervals (CIs) was obtained.

RESULTS

Thirty-nine articles met all inclusion criteria and were included in the meta-analysis including 22101 CRC cases and 23696 healthy controls. The 39 articles consisted of five VDR gene polymorphisms including ApaI, FokI, BsmI, TaqI and Cdx2. The results of meta-analysis showed that the FokI polymorphism was on the fringe of statistically significant in the comparisons of F allele vs. f allele in fixed model (OR = 1.029, 95% CI = 0.999-1.059, Praw = 0.057, PFDR = 0.057). Moreover, for the associations between BsmI polymorphism with CRC, We observed significant differences in allele frequencies, the homozygous model and the dominant model between CRC patients and healthy controls (B vs. b: OR = 0.862, 95% CI = 0.761-0.976, Praw = 0.019, PFDR = 0.019; BB vs. bb: OR = 0.786, 95% CI = 0.636-0.972, Praw = 0.026, PFDR = 0.039; BB + Bb vs. bb: OR = 0.934, 95% CI = 0.888-0.982, Praw = 0.008, PFDR = 0.024, respectively).

CONCLUSIONS

This meta-analysis suggests that BsmI is associated with CRC risk and FokI might be a risk factor for CRC. However, these associations with CRC need further studied.

A Polymorphism within the Vitamin D Transporter Gene Predicts Outcome in Metastatic Colorectal Cancer Patients Treated with FOLFIRI/Bevacizumab or FOLFIRI/Cetuximab

Purpose: Vitamin D exerts its inhibitory influence on colon cancer growth by inhibiting Wnt signaling and angiogenesis. We hypothesized that SNPs in genes involved in vitamin D transport, metabolism, and signaling are associated with outcome in metastatic colorectal cancer (mCRC) patients treated with first-line FOLFIRI and bevacizumab.Experimental Design: 522 mCRC patients enrolled in the FIRE-3 (discovery cohort) and TRIBE (validation set) trials treated with FOLFIRI/bevacizumab were included in this study. 278 patients receiving FOLFIRI and cetuximab (FIRE-3) served as a control cohort. Six SNPs in 6 genes (GC, CYP24A1, CYP27B1, VDR, DKK1, CST5) were analyzed.Results: In the discovery cohort, AA carriers of the GC rs4588 SNP encoding for the vitamin D-binding protein, and treated with FOLFIRI/bevacizumab had a shorter overall survival (OS) than those harboring any C allele (15.9 vs. 25.1 months) in both univariable (P = 0.001) and multivariable analyses (P = 0.047). This association was confirmed in the validation cohort in multivariable analysis (OS 18.1 vs. 26.2 months, HR, 1.83; P = 0.037). Interestingly, AA carriers in the control set exhibited a longer OS (48.0 vs. 25.2 months, HR, 0.50; P = 0.021). This association was further confirmed in a second validation cohort comprising refractory mCRC patients treated with cetuximab ± irinotecan (PFS 8.7 vs. 3.7 months) in univariable (P = 0.033) and multivariable analyses (P = 0.046).Conclusions:GC rs4588 SNP might serve as a predictive marker in mCRC patients treated with FOLFIRI/bevacizumab or FOLFIRI/cetuximab. Whereas AA carriers derive a survival benefit with FOLFIRI/cetuximab, treatment with FOLFIRI/bevacizumab is associated with a worse outcome. Clin Cancer Res; 24(4); 784-93. ©2017 AACR.

Vitamin D receptor and calcium-sensing receptor polymorphisms and colorectal cancer survival in the Newfoundland population

Background:

Increased serum levels of vitamin D and calcium have been associated with lower risks of colorectal cancer (CRC) incidence and mortality. These inverse associations may be mediated by the vitamin D receptor (VDR) and the calcium-sensing receptor (CASR). We investigated genetic variants in VDR and CASR for their relevance to CRC prognosis.

Methods:

A population-based cohort of 531 CRC patients diagnosed from 1999 to 2003 in Newfoundland and Labrador, Canada, was followed for mortality and cancer recurrence until April 2010. Germline DNA samples were genotyped with the Illumina Omni-Quad 1 Million chip. Multivariate Cox models assessed 41 tag single-nucleotide polymorphisms and relative haplotypes on VDR and CASR in relation to all-cause mortality (overall survival, OS) and disease-free survival (DFS).

Results:

Gene-level associations were observed between VDR and the DFS of rectal cancer patients (P=0.037) as well as between CASR and the OS of colon cancer patients (P=0.014). Haplotype analysis within linkage blocks of CASR revealed the G-G-G-G-G-A-C haplotype (rs10222633-rs10934578-rs3804592-rs17250717-A986S-R990G-rs1802757) to be associated with a decreased OS of colon cancer (HR, 3.15; 95% CI, 1.66–5.96). Potential interactions were seen among prediagnostic dietary calcium intake with the CASR R990G (P_int=0.040) and the CASR G-T-G-G-G-G-C haplotype for rs10222633-rs10934578-rs3804592-rs17250717-A986S-R990G-rs1802757 (P_int=0.017), with decreased OS time associated with these variants limited to patients consuming dietary calcium below the median, although the stratified results were not statistically significant after correction for multiple testing.

Conclusions:

Polymorphic variations in VDR and CASR may be associated with survival after a diagnosis of CRC.

Vitamin D Receptor Genotype, Vitamin D3 Supplementation, and Risk of Colorectal Adenomas: A Randomized Clinical Trial

Importance

Despite epidemiological and preclinical evidence suggesting that vitamin D and calcium inhibit colorectal carcinogenesis, daily supplementation with these nutrients for 3 to 5 years was not found to significantly reduce the risk of recurrent colorectal adenomas in a recent randomized clinical trial.

Objective

To investigate whether common variants in 7 vitamin D and calcium pathway genes (VDR, GC, DHCR7, CYP2R1, CYP27B1, CYP24A1, and CASR) modify the effects of vitamin D3 or calcium supplementation on colorectal adenoma recurrence.

Design, Setting, and Participants

We examined 41 candidate single-nucleotide polymorphisms (SNPs) in 2259 participants in a randomized, double-blind, placebo-controlled trial conducted at 11 clinical centers in the United States. Eligibility criteria included a recently diagnosed adenoma and no remaining colorectal polyps after complete colonoscopy. The study's treatment phase ended on August 31, 2013, and the analysis for the present study took place from July 28, 2014, to October 19, 2016.

Interventions

Daily oral supplementation with vitamin D3 (1000 IU) or calcium carbonate (1200 mg elemental calcium) or both or neither.

Main Outcomes and Measures

The outcomes assessed were the occurrence of 1 or more adenomas or advanced adenomas (estimated diameter, ≥1 cm; or with villous histologic findings, high-grade dysplasia, or cancer) during follow-up. Treatment effects and genotype associations and interactions were estimated as adjusted risk ratios (RRs) and 95% confidence intervals (CIs). The effective number of independent SNPs was calculated to correct for multiple testing.

Results

Among the 2259 participants randomized, 1702 were non-Hispanic whites who completed the trial and had genotype data for analysis (1101 men; mean [SD] age 58.1 [6.8] years). The effect of vitamin D3 supplementation on advanced adenomas, but not on adenoma risk overall, significantly varied according to genotype at 2 VDR SNPs (rs7968585 and rs731236) in linkage disequilibrium (D' = 0.98; r2 = 0.6). For rs7968585, among individuals with the AA genotype (26%), vitamin D3 supplementation reduced risk by 64% (RR, 0.36; 95% CI, 0.19-0.69; P = .002; absolute risk decreased from 14.4% to 5.1%). Among individuals with 1 or 2 G alleles (74%), vitamin D3 supplementation increased risk by 41% (RR, 1.41; 95% CI, 0.99-2.00; P = .05; absolute risk increased from 7.7% to 11.1%; P < .001 for interaction). There were no significant interactions of genotypes with calcium supplementation.

Conclusions and Relevance

Our findings suggest that benefits from vitamin D3 supplementation for the prevention of advanced colorectal adenomas may vary according to vitamin D receptor genotype.

Trial Registration

clinicaltrials.gov Identifier: NCT00153816.

Correlation between polymorphism of vitamin D receptor TaqI and susceptibility to colorectal cancer: A meta-analysis

The meta-analysis aimed to investigate the correlation between the polymorphism of the vitamin D receptor (VDR) TaqI and susceptibility of colorectal cancer.Studies were extracted from the electronic databases of PubMed and Embase. The balance of heredity was estimated by the Hardy-Weinberg equilibrium test, and heterogeneity was assessed by Cochran Q statistics and I test. Four assessed models, namely additive (t vs T), dominant (Tt + tt vs TT), recessive (tt vs Tt + TT), and codominant (Tt vs TT and tt vs TT), were used to evaluate the correlations and the effective results were measured as odds ratio (OR) with 95% confidence interval (CI).A total of 14 studies, including 4632 patients and 5086 controls, were enrolled in this meta-analysis. With no significant heterogeneities observed among the 4 models, the fixed-effect model was used to examine the pooled effect value. There were no significant differences among t vs T (OR = 1.01; 95% CI, 0.94-1.09; P = .70), Tt + tt vs TT (OR = 1.05; 95% CI, 0.96-1.15; P = .32), tt vs Tt + TT (OR = 1.01; 95% CI, 0.87-1.17; P = .92), Tt vs TT (OR = 1.03; 95% CI, 0.93-1.13; P = .62), and tt vs TT (OR = 1.00; 95% CI, 0.85-1.17; P = .98) with respect to increasing CRC frequency.No evidence showed that TaqI polymorphisms were significantly associated with susceptibility to CRC.

Genetic polymorphisms of vitamin D receptor (VDR), CYP27B1 and CYP24A1 genes and the risk of colorectal cancer

INTRODUCTION

Vitamin D receptor (VDR) and proteins encoded by the genes CYP27B2 and CYP24A1 involved in the production and inactivation of vitamin D can influence vitamin D and the susceptibility to colorectal cancer (CRC). The objective of this study was to investigate the relationship between the risk of CRC and polymorphisms in VDR, CYP27B1 and CYP24A1, lifestyle and dietary habits.

METHODS

The study included 152 patients with CRC and 321 controls. All participants answered a questionnaire on their dietary habits, alcohol consumption and smoking habits. DNA was extracted from peripheral blood. Polymorphisms of BsmI and ApaI were identified by performing PCR-RFLP. Identification of CYP24A1 (rs6013897, rs158552 and rs17217119) and CYP27B1 (rs10877012) polymorphisms was performed by gene sequencing.

RESULTS

Smoking, alcohol use, and low or no consumption of fruit, cereals and dairy products were associated with an increased risk of CRC. A heterozygous genotype Aa or an association genotype aa + Aa of the VDR ApaI polymorphism increased the risk of CRC. The VDR BsmI polymorphism was not significantly associated with the risk of CRC. Multivariate analysis showed that heterozygous and association genotype AT + AA of the rs6013897 polymorphism, genotype CT of the rs158552 polymorphism, association genotype CT + CC and genotypes AA and GG of the rs17217119 polymorphism of CYP24A1, and heterozygous genotype GT and association genotype GT + TT of the rs10877012 polymorphism in CYP27B1 were associated with a higher risk of CRC.

CONCLUSIONS

Dietary habits, lifestyle, and polymorphisms in VDR (ApaI), CYP24A1 (rs6013897, rs158552, rs17217119) and CYP27B1 (rs10877012) were associated with a higher risk of CRC.

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.

Role of vitamin D receptor gene Cdx2 and Apa1 polymorphisms in prostate cancer susceptibility: a meta-analysis

BACKGROUND

Vitamin D receptor (VDR) gene polymorphisms affect the risk of prostate cancer. However, studies investigating the relationship between VDR gene polymorphisms (Cdx2 and ApaI) and prostate cancer risk are equivocal. Therefore, we conducted a meta-analysis of all the studies to review the evidence available.

METHODS

A comprehensive search of PubMed, EMBASE, and ISI Web of Science for studies published until September 2015 was conducted. Odds ratios (ORs) and 95 % confidence intervals (CIs) were analyzed to determine the association between VDR Cdx2 and ApaI polymorphisms, and prostate cancer risk.

RESULTS

The meta-analysis included 10 studies involving 4979 cases and 4380 controls to analyze the VDR Cdx2 polymorphism. An additional 11 studies involving 2837 cases and 2884 controls were analyzed for the VDR ApaI polymorphism. Evidence failed to support the role of VDR Cdx2 and ApaI polymorphisms in prostate cancer. For Cdx2, the pooled OR was 1.11 (95 % CI = 0.93-1.33) for AA vs. GG genotypes, 0.97 (95 % CI = 0.88-1.06) for GA vs. AA genotypes, 0.99 (95 % CI = 0.91-1.08) for AA + GA vs. GG, and 1.12 (95 % CI = 0.95-1.31) for AA vs. GA + GG. No significant relationship was observed in any subgroup analysis based on ethnicity, controls, and Hardy-Weinberg equilibrium (HWE). ORs for the ApaI polymorphism were similar.

CONCLUSIONS

VDR Cdx2 and ApaI polymorphisms are not associated with prostate cancer. Additional evidence is required to confirm this conclusion.

Association of vitamin D receptor gene polymorphisms and serum 25-hydroxyvitamin D levels with Crohn's disease in Chinese patients

BACKGROUND AND AIM

The vitamin D receptor (VDR) regulates immune responses and inflammation through binding with 1,25-dihydroxyvitamin D, the active form of vitamin D. The serum 25-hydroxyvitamin D (25(OH)D) level clinically reflects vitamin D status in the human body. We investigated the association of VDR polymorphisms and 25(OH)D levels in Chinese patients with Crohn's disease (CD).

METHODS

Vitamin D receptor polymorphisms (FokI, BsmI, ApaI, and TaqI) were genotyped by SNaPshot. Serum 25(OH)D levels were measured by electro-chemiluminescence immunoassay.

RESULTS

A total of 297 patients with CD and 446 controls were recruited. Compared with controls, mutant alleles and genotypes of BsmI and TaqI were less prevalent in patients with CD (all P < 0.05/4 = 0.0125). The AAC haplotype formed by BsmI, ApaI, and TaqI was also less prevalent in patients with CD (P = 0.004). Furthermore, 124 patients and 188 controls were randomly selected for measurements of 25(OH)D levels. Average 25(OH)D level was lower in patients with CD than in controls (15.46 ± 8.11 vs 21.64 ± 9.45 ng/mL, P < 0.001) and negatively linked to CD activity index (β = -0.829, P < 0.001), platelet count (β = -0.253, P < 0.001) and neutrophil percentage (β = -0.136, P = 0.005) in patients with CD. The ApaI mutant genotype and vitamin D deficiency (<20 ng/mL) were independently associated with CD (P = 0.009, P < 0.001, respectively). In patients with CD, vitamin D deficiency interacted with FokI, ApaI, and TaqI mutant genotypes (P = 0.027, P = 0.024, and P = 0.040, respectively).

CONCLUSIONS

Vitamin D receptor (BsmI, ApaI, and TaqI) mutations and lower 25(OH)D levels are associated with CD in Chinese patients. Moreover, VDR (FokI, ApaI, and TaqI) mutations and vitamin D deficiency may have a combined impact on CD.

Associations between vitamin D receptor (VDR) gene polymorphisms and colorectal cancer risk and effect modifications of dietary calcium and vitamin D in a Japanese population

Much interest has been drawn to possible associations between vitamin D receptor (VDR) gene polymorphisms and colorectal cancer risk in conjunction with potentially protective effects of calcium and vitamin D. In a study of 685 cases of colorectal cancer and 778 community controls in Japan, we examined the associations of the FokI, BsmI, ApaI, and TaqI polymorphisms with colorectal cancer risk and effect modification by dietary calcium and vitamin D. Genotypes were determined by the PCR-RFLP method. The ApaI polymorphism seemed to be associated with a decreased risk of colorectal cancer, particularly of rectal cancer. The adjusted odds ratio of colorectal cancer for the ApaI AA and Aa genotypes combined versus the aa genotype was 0.83 (95% confidence interval [CI] 0.67-1.02), and the corresponding value for rectal cancer was 0.75 (95%CI 0.56-0.99). A decreased risk of colorectal cancer for the ApaI AA and Aa genotypes combined was more evident in individuals with high calcium intake (interaction p=0.055). The FokI polymorphism seemed to be associated with a decreased risk of colon cancer among those with high vitamin D intake (interaction p=0.09). The BsmI and TaqI polymorphisms were unrelated to colorectal cancer risk, and the null associations were not modified by calcium or vitamin D intake. In conclusion, the ApaI polymorphism may be associated with a decreased risk of colorectal cancer in Japanese, dependent on dietary calcium intake.

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.

Vitamin D, Cancer Risk, and Mortality

Antiproliferative effects of 1,25-dihydroxyvitamin D, the biologically active form of vitamin D, are well established in various cell types by influencing cell differentiation and decreasing cell proliferation, growth, invasion, angiogenesis, and metastasis. Several meta-analyses showed that low serum levels of 25(OH)D was associated with colorectal cancer and overall mortality, while the association with cancer mortality was less consistent. VDR is a crucial mediator for the cellular effects of vitamin D and conflicting data have been reported for most malignancies. Beyond VDR, the biological effects of vitamin D are mediated by the vitamin D-binding protein. The GC (group-specific component) gene, encoding DBP, is highly polymorphic and several polymorphisms were investigated in association with cancer development with controversial results. Vitamin D supplementation was found to be associated with a reduced risk of overall mortality, reviewing all published trials on healthy subjects, whereas the evidence of an effect on cancer risk and mortality is less clear. Furthermore, long-term health effects of high doses of vitamin D, extended duration of supplementation, and the association with different baseline vitamin D levels remain to be investigated. In summary, epidemiological and preclinical studies support the development of vitamin D as preventative and therapeutic anticancer agents, with significant associations especially found for low vitamin D status with overall mortality and cancer outcome, more than cancer incidence. However, a definitive conclusion cannot be drawn and only large randomized clinical trials, both in healthy subjects and in cancer patients, will allow to draw definitive conclusions on the effect of vitamin D supplementation on cancer risk, prognosis, and mortality.

Association between circulating vitamin D, the Taq1 vitamin D receptor gene polymorphism and colorectal cancer risk among Jordanians

BACKGROUND

The physiological role of vitamin D extends beyond bone health and calcium-phosphate homeostasis to effects on cancer risk, mainly for colorectal cancer. Vitamin D may have an anticancer effect in colorectal cancer mediated by binding of the active form 1,25(OH)2D to the vitamin D receptor (VDR). The Taq1 VDR gene polymorphism, a C-to-T base substitution (rs731236) in exon 9 may influence its expression and function. The aim of this study was to determine the 25(OH)D vitamin D level and to investigate the association between circulating vitamin D level and Taq1VDR gene polymorphism among Jordanian colorectal cancer patients.

MATERIALS AND METHODS

This case control study enrolled ninety-three patients and one hundred and two healthy Jordanian volunteers from AL-Basheer Hospital/Amman (2012-2013). Ethical approval and signed consent forms were obtained from all participants before sample collection. 25(OH)D levels were determined by competitive immunoassay Elecsys (Roche Diagnostic, France). DNA was extracted (Promega, USA) and amplified by PCR followed by VDR Taq1 restriction enzyme digestion. The genotype distribution was evaluated by paired t-test and chi-square. Comparison between vitamin D levels among CRC and control were assessed by odds ratio with 95% confidence interval.

RESULTS

The vitamin D serum level was significantly lower among colorectal cancer patients (8.34 ng/ml) compared to the healthy control group (21.02 ng/ml). Patients deficient in vitamin D (less than 10.0 ng/ml) had increased colorectal cancer risk 19.2 fold compared to control. Only 2.2% of CRC patients had optimal vitamin D compared to 23.5% among healthy control. TT, Tt and tt Taq1 genotype frequencies among CRC cases was 35.5%, 50.5% and 14% compared to 43.1%, 41.2% and 15.7% among healthy control; respectively. CRC patients had lower mean vitamin D level among TT (8.91 ± 4.31) and Tt (9.15 ± 5.25) genotypes compared to control ((21.3 ± 8.31) and (19.3 ± 7.68); respectively.

CONCLUSIONS

There is significant association between low 25(OH)D serum level and colorectal cancer risk. The VDRTaq1 polymorphism was associated with increased colorectal cancer risk among patient with VDRTaq1 TT and Tt genotypes. Understanding the functional mechanism of VDRTaq1 TT and Tt may provide a strategy for colorectal cancer prevention and treatment.

Role of vitamins in gastrointestinal diseases

A tremendous amount of data from research was published over the past decades concerning the roles of different vitamins in various gastrointestinal diseases. For instance, most vitamins showed an inverse relationship with the risk of colorectal carcinoma as well as other malignancies like gastric and esophageal cancer in observational trials, however interventional trials failed to prove a clear beneficial preventive role. On the other hand, more solid evidence was obtained from high quality studies for a role of certain vitamins in specific entities. Examples for this include the therapeutic role of vitamin E in patients with non-alcoholic steatohepatitis, the additive role of vitamins B₁₂ and D to the standard therapy of chronic hepatitis C virus, the role of vitamin C in reducing the risk of gallstones, the positive outcome with vitamin B₁₂ in patients with aphthous stomatitis, and the beneficial effect of vitamin D and B₁ in patients with inflammatory bowel disease. Other potential uses are yet to be elaborated, like those on celiac disease, pancreatic cancer, pancreatitis, cholestasis and other potential fields. Data from several ongoing interventional trials are expected to add to the current knowledge over the coming few years. Given that vitamin supplementation is psychologically accepted by patients as a natural compound with relative safety and low cost, their use should be encouraged in the fields where positive data are available.

Vitamin D receptor Cdx-2 polymorphism and premenopausal breast cancer risk in southern Pakistani patients

Background

Vitamin D3 is a secoster oid that exerts its effect by binding to its nuclear receptor called vitamin D receptor (VDR), inducing apoptosis and thereby inhibiting cell proliferation in cancer cells. The VDR receptor, located in the nucleus, is known to regulate the functions of over 200 genes. Various allelic forms of hVDR have been discovered that increase susceptibility to various cancers. The VDR-Cdx2 polymorphism, located in the promoter region of exon 1e in the VDR gene, influences the functional activity of the receptor, since the hVDR lacks consensus TATA and CAAT boxes. The current investigation examines the association between VDR-Cdx2 polymorphism and breast cancer in premenopausal females from Southern Pakistan.

Methods

We conducted a case control study on 264 subjects (103 cases and 161 controls) who were recruited from a tertiary hospital located in Karachi, Pakistan. Genomic DNA was extracted from peripheral blood using a commercial kit method, and the VDR-Cdx2 polymorphism was genotyped using tetraprimer amplification refractory mutation system polymerase chain reaction (T-ARMS-PCR) method. Pearson chi square test was used to assess the association between VDR-Cdx2 genotype and breast cancer while genotype distribution in controls was evaluated by Hardy-Weinberg equilibrium (HWE). Breast cancer risk was calculated using odds ratios and 95% confidence intervals.

Results

The genotype distribution in the control group was in HWE (p > 0.05) for the VDR-Cdx2 polymorphism. A non-significant association was observed between VDR cdx2 polymorphism and breast cancer, however the GG genotype was at risk (OR = 1.832, 95% CI = 0.695–4.828) of developing breast cancer.

Conclusion

The GG genotype of Cdx2-VDR gene polymorphism may increase the risk of developing breast cancer in young female patients in South Pakistan. Further investigations examining additional single nucleotide polymorphisms (SNPs) in VDR are required to assess their relationships with breast cancer.

Vitamin D receptor BsmI polymorphism and colorectal cancer risk: an updated analysis

BACKGROUND

Previous studies have investigated the association between the vitamin D receptor (VDR) BsmI polymorphism and colorectal cancer (CRC) susceptibility, but the results were conflicting. The aim of this study is to quantitatively summarize the relationship between this polymorphism and CRC risk.

MATERIALS AND METHODS

Two investigators independently searched the Medline, Embase, China National Knowledge Infrastructure (CNKI) and Chinese Biomedicine databases for studies published before November 2013. Summary odds ratios (ORs) and 95% confidence intervals (95%CIs) for VDR BsmI polymorphism and CRC were calculated in a fixed- effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate.

RESULTS

This meta-analysis included 14 case-control studies, which included 10,822 CRC cases and 11,779 controls. Overall, the variant genotype (BB) of the BsmI was associated with a lower CRC risk when compared with the wild-type bb homozygote (OR=0.66, 95%CI: 0.49-0.88). Similarly, a decreased CRC risk was also found in the dominant and recessive models. When stratifying for ethnicity, source of controls, and study sample size, associations were observed among Caucasians, population-based studies and studies with large study sample size (>1000 subjects). Limiting the analysis to the studies within Hardy-Weinberg equilibrium, the results were persistent and robust. No publication bias was found in the present study.

CONCLUSIONS

This updated meta-analysis suggests that the VDR BsmI polymorphism may be associated with a moderate protective effect against CRC.

Dietary n-3/long-chain n-3 polyunsaturated fatty acids for prevention of sporadic colorectal tumors: a randomized controlled trial in polypectomized participants

To address preventive effects of n-3 PUFAs/LC n-3 PUFAs on CRTs, a randomized controlled trial was conducted. One-hundred four experimental group participants were advised to increase intake of n-3 PUFAs, including fish/shell fish, fish oil supplements and perilla oils, and to decrease consumption of n-6 PUFAs and fats/oils as a whole for 24 months. One-hundred one control group participants were only cautioned to reduce consumption of fats/oils as a whole. Random allocation was satisfactorily attained, and participants sufficiently complied with our regimen. Intakes, plasma concentrations, and compositions of the RBC and sigmoid colon membranes of n-3 PUFAs, LC n-3 PUFAs, EPA and DHA increased, and the ratios of n-6 PUFAs/n-3 PUFAs and AA/LC n-3 PUFAs decreased without any adverse response. Twenty-four months after the intervention, the multivariate-adjusted hazard ratio (95% confidence intervals) was estimated to be 0.805 (0.536-1.209) with a signal towards the reduced CRT incidence.

An integrated approach to defining genetic and environmental determinants for major clinical outcomes involving vitamin D

There is substantial genetic and epidemiological evidence implicating vitamin D in the pathogenesis of many common diseases. A number of studies have sought to define an association for disease with sequence variation in the VDR gene, encoding the ligand-activated nuclear hormone receptor for vitamin D. The results of such studies have been difficult to replicate and are likely to need to account for specific environmental exposures. Here, we review recent work that has begun to study the interactions between VDR gene polymorphisms, vitamin D blood levels, and complex disease susceptibility, notably in the context of major clinical outcomes. We highlight the challenges moving forward in this area and its importance for effective clinical translation of current research.

Associations among four polymorphisms (BsmI, FokI, TaqI and ApaI) of vitamin D receptor gene and end-stage renal disease: a meta-analysis

BACKGROUND AND AIMS

To evaluate the association between vitamin D receptor (VDR) BsmI, FokI, TaqI and ApaI gene polymorphisms and the risk of end-stage renal disease (ESRD).

METHODS

All eligible studies were included in our meta-analysis of a search of the PubMed, Cochrane and China National Knowledge Infrastructure (CNKI) databases according to predefined criteria. The fixed-effects or random-effects models were used to calculate the pooled odds ratio (OR) and corresponding 95% confidence interval (CI).

RESULTS

Thirteen studies including 1510 patients and 1812 controls were recruited for the analysis of the association between the VDR BsmI, FokI, TaqI and ApaI gene polymorphisms and the risk of ESRD.VDR BsmI B allele, BB genotype and bb genotype, FokI F allele, FF genotype and ff genotype, TaqI T allele, TT genotype and tt genotype, ApaI A allele, AA genotype and aa genotype were not associated with ESRD susceptibility for overall populations, Asians and Caucasians.

CONCLUSIONS

Results from the current study suggest that VDR BsmI, FokI, TaqI and ApaI gene polymorphisms are not associated with the risk of ESRD in the overall populations, Asians and Caucasians. However, more studies should be performed in the future.

Predicting response to vascular endothelial growth factor inhibitor and chemotherapy in metastatic colorectal cancer

BACKGROUND

Bevacizumab improves progression free survival (PFS) and overall survival (OS) in metastatic colorectal cancer patients however currently there are no biomarkers that predict response to this treatment. The aim of this study was to assess if differential protein expression can differentiate patients who respond to chemotherapy and bevacizumab, and to assess if select proteins correlate with patient survival.

METHODS

Pre-treatment serum from patients with metastatic colorectal cancer (mCRC) treated with chemotherapy and bevacizumab were divided into responders and nonresponders based on their progression free survival (PFS). Serum samples underwent immunoaffinity depletion and protein expression was analysed using two-dimensional difference gel electrophoresis (2D-DIGE), followed by LC-MS/MS for protein identification. Validation on selected proteins was performed on serum and tissue samples from a larger cohort of patients using ELISA and immunohistochemistry, respectively (n = 68 and n = 95, respectively).

RESULTS

68 proteins were identified following LC-MS/MS analysis to be differentially expressed between the groups. Three proteins (apolipoprotein E (APOE), angiotensinogen (AGT) and vitamin D binding protein (DBP)) were selected for validation studies. Increasing APOE expression in the stroma was associated with shorter progression free survival (PFS) (p = 0.0001) and overall survival (OS) (p = 0.01), DBP expression (stroma) was associated with shorter OS (p = 0.037). Increasing APOE expression in the epithelium was associated with a longer PFS and OS, and AGT epithelial expression was associated with a longer PFS (all p < .05). Increasing serum AGT concentration was associated with shorter OS (p = 0.009).

CONCLUSIONS

APOE, DBP and AGT identified were associated with survival outcomes in mCRC patients treated with chemotherapy and bevacizumab.

Vitamin D receptor gene polymorphisms in relation to the risk of colorectal cancer in the Polish population

The protective effect of vitamin D against several cancers including colorectal cancer is modulated by the vitamin D receptor (VDR) and its ligand, the active form of vitamin D. VDR response has been found to play a role in various genes encoding proteins involved in crucial cellular pathways. Single nucleotide polymorphisms (SNPs) of the VDR gene that modulate its activity are located in the promoter region, exons 2–9, and their vicinity and also in the 3′UTR region. Some of them have been previously studied in relation to cancer susceptibility and prognosis. The aim of our study was to investigate four polymorphisms, BsmI, ApaI, TaqI, and FokI, of the VDR gene in Polish patients with sporadic colorectal cancer and to evaluate their association with susceptibility to cancer. We found a significant association between the BsmI genotype and cancer (individuals with the bb genotype are more susceptible to cancer compared to those with other genotypes, p = 0.025, Fisher’s exact test for 2 × 2 table). Also, the TT genotype at TaqI and the AA genotype at ApaI are correlated with a higher risk of cancer (p = 0.00071 and p = 1.0 × 10⁻⁵, respectively). We found relatively strong linkage disequilibrium between the TaqI and ApaI loci (T with A and t with a, respectively). Both of these loci are associated with cancer. We do not observe any such association for the FokI polymorphism. In conclusion, a small modification in VDR expression may play a role in such a multipathway process as tumorigenesis.

A miRNA-binding site single nucleotide polymorphism in the 3'-UTR region of the NOD2 gene is associated with colorectal cancer

Colorectal cancer (CRC) is one of the common malignancies worldwide. Single nucleotide polymorphisms in miRNA-binding site on gene transcripts are reported to play important role in increased risk of CRC in different population. We performed a case-control study using 88 CRC patients and 88 non-cancer counterparts to evaluate the association between NOD2 rs3135500 polymorphism located at 3' untranslated region of the gene and risk of sporadic CRC. Genotyping of rs3135500 polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. We found a significant association of AA genotype with risk of CRC (adjusted OR 3.100, CI 1.621-5.930, p < 0.001). Also, significant difference in physical activity (p = 0.001) between case and control groups was found. We also found that individuals in control group were more aspirin or NSAID user compared to sporadic CRC cases (p = 0.002). In the case group, individuals with GG genotype consumed more aspirin or NSAID compared with AA+AG genotypes (33.3 vs. 9.6 %, adjusted OR 4.71, CI 1.25-17.76, p = 0.02). However, in the control group, individuals with AA+AG genotypes used more aspirin or NSAID compared with GG genotypes (47.2 vs. 11.4 %, adjusted OR 14 %, CI 0.05-0.47, p < 0.001).

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

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

Significance of vitamin d receptor gene polymorphisms for risk of hepatocellular carcinoma in chronic hepatitis C

BACKGROUND/AIMS

Biological and epidemiological data suggest that vitamin D levels may influence cancer development. Several single nucleotide polymorphisms have been described in the vitamin D receptor (VDR) gene in association with cancer risk. We aimed to investigate the association of VDR gene polymorphisms with hepatocellular carcinoma (HCC) development in chronic hepatitis C patients.

METHODS

In a cross-sectional, hospital-based setting, 340 patients (201 chronic hepatitis, 47 cirrhosis and 92 HCC) and 100 healthy controls receiving VDR genotyping (bat-haplotype: BsmI rs1544410 C, ApaI rs7975232 C and TaqI rs731236 A) were enrolled.

RESULTS

Patients with HCC had a higher frequency of ApaI CC genotype (P = 0.027) and bAt[CCA]-haplotype (P = 0.037) as compared to control subjects. There were no differences in BsmI and TaqI polymorphisms between two groups. In patients with chronic hepatitis C, HCC subjects had a higher frequency of ApaI CC genotype and bAt[CCA]-haplotype than those with chronic hepatitis (P = 0.001 and 0.002, respectively) and cirrhosis (P = 0.019 and 0.026, respectively). After adjusting age and sex, logistic regression analysis showed that ApaI CC genotype (odds ratio: 3.02, 95% confident interval: 1.65-5.51) was independently associated with HCC development.

CONCLUSION

VDR ApaI polymorphism plays a role in the development of HCC among chronic hepatitis C patients. Further explorations of this finding and its implications are required.

Role of the VDR Bsm I and Apa I polymorphisms in the risk of colorectal cancer in Kashmir

OBJECTIVE

A case-control study aiming to evaluate the relationship between Bsm I and Apa I restriction fragment gene polymorphisms and colorectal cancer (CRC) was carried out in Kashmir, including a total of 368 subjects (180 cases and 188 controls).

METHODS

DNA samples extracted from the blood of the subjects were analyzed for 3' untranslated region (3' UTR) Apa I and Bsm I polymorphisms using restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR).

RESULTS

A statistically significant 2.7-fold increased risk was observed in individuals found homozygous for the presence of the 'b' allele, in comparison to subjects homozygous for the 'B' allele (odds ratio (OR) 2.7, 95% confidence interval (CI) 1.49-4.86 (Bsm I)), and a statistically insignificant 2-fold increased risk was found among individuals with the 'aa' genotype, as compared to subjects with the 'AA' genotype (OR 2.017, 95% CI 0.86-4.7). Our study also yielded statistically significant results when the Apa I polymorphism was stratified by age (≤ 50 years) and dwelling area (rural area), and the Bsm I polymorphism by gender (male gender), suggesting a possible role of Apa I and Bsm I polymorphisms in the etiology of CRC in Kashmir.

CONCLUSION

We conclude that Apa I and Bsm I single-nucleotide polymorphisms (SNPs) in the vitamin D receptor gene (VDR) might be associated with susceptibility to CRC among Kashmiris.

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.