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

Genetic Diversity in Bronchial Asthma Susceptibility: Exploring the Role of Vitamin D Receptor Gene Polymorphisms in Varied Geographic Contexts

Bronchial asthma (BA) exhibits varying prevalence across global populations, prompting a comprehensive investigation into genetic and environmental determinants. Vitamin D is a potent immunomodulator capable of suppressing inflammatory signals in several cell types involved in the asthmatic response; it exerts effects on the immune system by binding to the nuclear vitamin D receptor (VDR). VDR gene genetic variations are affecting serum vitamin D levels with a possible role in the BA risk. The current study aimed to examine the complex interaction of various factors (genetic background, serum vitamin D levels, and geographic location) to identify differences in the influence of these factors on the susceptibility to asthma between populations at different latitudes. Focusing on Eastern European cohorts from Latvia and Lithuania and comparing them with published data on East Asian populations, we explore the impact of VDR gene polymorphisms on BA susceptibility. Genotyping four key VDR SNPs and assessing their association with 25-hydroxyvitamin D levels, our study unveils significant associations of the studied loci with the risk of asthma-both risk-reducing and increasing effects, differently distributed between Baltic and East Asian populations. The functional effects of in silico VDR gene genetic variations are also identified and discussed.

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.

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 (VDR) Gene Polymorphism in Patients Diagnosed with Colorectal Cancer

Colorectal cancer (CRC) is one of the most commonly occurring neoplasias in humans. The prevalence of CRC rates is still rising. Although the exact background of the disease still remains unknown, it is believed that CRC may not only be a result of environmental factors, but also genetic ones. One of the mechanisms underlying CRC might be the vitamin D pathway, as CRC is the most closely linked neoplasia to vitamin D deficiency. This study shows a possible association of the vitamin D receptor (VDR) polymorphisms FokI, BsmI, ApaI, and TaqI with CRC susceptibility. A total of 103 patients diagnosed with CRC (61 men and 42 women, aged 57-82 years) and 109 healthy people (50 men and 59 women, aged 47-68 years) were genotyped using PCR-RFLP for FokI, BsmI, ApaI, and TaqI. None of the single nucleotide polymorphisms (SNPs) individually increased or decreased the risk of CRC. The evaluation of haplotypes revealed two that might enhance the likelihood of CRC development: taB (OR = 30.22; 95% CI 2.81-325.31; p = 0.01) and tAb (OR = 3.84; 95% CI 1.29-11.38; p = 0.01). In conclusion, genotyping is an easy and robust procedure that needs to be performed only once in a lifetime. A creation of a relevant SNP's panel might contribute to the identification of the groups that are at the greatest risk of CRC.

Ethnicity as modifier of risk for Vitamin D receptors polymorphisms: Comprehensive meta-analysis of all cancer sites

Vitamin D receptors polymorphisms are found to be associated with several cancers. Since their prevalence vary across ethnicities and ethnicity itself seems to influence the cancer risk, a comprehensive meta-analysis was performed to investigate the role of VDR Fok1, Bsm1, Taq1, Apa1, Cdx2 and cancer risk at specific organ sites. Odds ratios, calculated with random-effects models, summarized one-hundred-ninety-two independent studies for twenty-two cancer sites. Evidence was provided that Fok1, Bsm1, Cdx2, Apa1 and Taq1 are linked to cancer susceptibility for colorectal, lung, ovarian, skin, multiple myeloma and brain cancer. Stratifying by ethnicity, some differences were found, partially explained by minor allele frequency (MAF), for colorectal cancer, ovarian and prostate cancer in Caucasian and prostate cancer in Asian populations. In summary, ethnicity may be a modifier of cancer risk, in particular for hormone dependent cancers and it should be considered evaluating the effect of VDR on cancer risk.

Vitamin D Receptor Polymorphisms and Cancer

Increasing scientific evidence supports the link between vitamin D and cancer risk. The active metabolite 1,25(OH)2D exerts its activity by binding to the vitamin D receptor (VDR), an intracellular receptor that mediates transcriptional activation and repression of target genes. The binding of 1,25(OH)2D to VDR is able to regulate hundreds of different genes. VDR is active in virtually all tissues including the colon, breast, lung, ovary, bone, kidney, parathyroid gland, pancreatic b-cells, monocytes, T lymphocytes, melanocytes, keratinocytes, and also cancer cells.The relevance of VDR gene restriction fragment length polymorphisms for various types of cancer has been investigated by a great number of studies.We have carried out a systematic review of the literature to analyze the relevance of more VDR polymorphisms (Fok1, Bsm1, Taq1, Apa1, and Cdx2) for individual malignancies considering ethnicity as a key factor for heterogeneity.Up to December 2018, we identified 176 independent studies with data to assess the risk of breast, prostate, colorectal, skin (melanoma and non-melanoma skin cancer), lung, ovarian, kidney, bladder, gallbladder, esophageal, thyroid, head and neck, liver and pancreatic cancer, oral squamous cell carcinoma, non-Hodgkin lymphoma, multiple myeloma and sarcoma.Significant associations with VDR polymorphisms have been reported for prostate (Fok1, Bsm1, Taq1, Apa1, Cdx2), breast (Fok1, Bsm1, Taq1, Apa1, CdX2), colorectal (Fok1, Bsm1, Taq1, Apa1), and skin cancer (Fok1, Bsm1, Taq1). Very few studies reported risk estimates for the other cancer sites.Conflicting data have been reported for most malignancies, and at present, it is still not possible to make any definitive statements about the importance of the VDR genotype for cancer risk. It seems probable that other factors such as ethnicity, phenotype, 25(OH)D plasma levels, and UV radiation exposure play a role as confounding factors and introduce heterogeneity.To conclude, there is some indication that VDR polymorphisms may modulate the risk of some cancer sites and in future studies VDR genetic variation should be integrated also with assessment of vitamin D status and stratified by ethnicity.

TaqI and ApaI Variants of Vitamin D Receptor Gene Increase the Risk of Colorectal Cancer in a Saudi Population

Background:

Polymorphisms in the gene encoding the vitamin D receptor (VDR) affect the protective role of vitamin D against many types of cancers, including colorectal cancer (CRC).

Objective:

The objective of this study was to assess the effect of four major polymorphisms of the VDR gene (ApaI, TaqI, BsmI and FokI) on the risk of CRC in a Saudi population.

Materials and Methods:

This case–control study recruited 132 CRC patients from the oncology clinics at King Abdulaziz University Hospital and 124 healthy controls from the blood bank at King Fahad General Hospital, Jeddah, Saudi Arabia, between September 2017 and August 2018. All participants were Saudis and aged 20–80 years. Genomic DNA samples were extracted from the peripheral blood cells and amplified with polymerase chain reaction. The resulting fragments were digested with different endonucleases to reveal the genotypes using the restriction fragment length polymorphism technique. The genotype distribution and allele frequency, odds ratio (OR), risk ratio (RR) and P values were determined with contingency table analysis following Hardy–Weinberg equilibrium equation.

Results:

For the ApaI single-nucleotide polymorphism (SNP) (rs7975232), only the heterozygous (Aa) genotype increased the risk of CRC (OR = 3.4, RR = 2.3, and P < 0.0001), whereas the TaqI SNP (rs731236) carriers with either the heterozygous (Tt) or homozygous (tt) genotype displayed an increased risk for the disease (OR = 6.18, RR = 4, P < 0.0001; OR = 3, RR = 2.4, P = 0.02, respectively). In contrast, heterozygous (Bb) and homozygous (bb) carriers of the BsmI SNP (rs1544410) had significantly lower risk for CRC (P < 0.0001). Finally, for the FokI SNP (rs2228570), there was no association with CRC risk.

Conclusion:

This study found that VDR SNPs ApaI and TaqI increase the risk of CRC, whereas BsmI reduces the risk of CRC in the selected Saudi population. Therefore, ApaI and TaqI SNPs could potentially be used as a diagnostic biomarker for CRC. However, the molecular mechanisms by which these variants increase or decrease the risk of CRC need to be investigated.

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.

Bone Mineral Density and Vitamin D Receptor Genetic Variants in Egyptian Children with Beta Thalassemia Major on Vitamin D Supplementation

Background

Low bone mineral density (BMD) is a characteristic feature of Beta thalassemia major (βTM) patients. Vitamin D is important for bone mineralization. Vitamin D receptors (VDR) genetic variants may be related to vitamin D status and BMD.

Objectives

To evaluate the effect of VDR genetic variants on vitamin D levels and BMD in βTM Egyptian patients supplemented with vitamin D.

Methods

This study was conducted on forty children with βTM and seventeen unrelated healthy sex and age-matched controls. Serum calcium, phosphorus, alkaline phosphatase, ferritin, and vitamin D were measured. VDR genetic variants (BsmI, TaqI, and FokI) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). BMD was measured by dual-energy X-ray densitometry (DEXA) of the lumbar spine.

Results

In βTM patients, 22.5% had insufficient, and 77.5% had sufficient levels of vitamin D, and no cases had vitamin D deficient. BMD Z score was significantly lower in βTM patients compared to controls (p<0.001). Osteopenia and osteoporosis of lumbar spines were observed in 70% and 22.5% of βTM patients respectively. BsmI bb and FokI Ff and ff genotypic variants were significantly associated with lower vitamin D and BMD Z score. No association was observed with TaqI genotypic variants.

Conclusions

Low BMD is prevalent in patients with βTM despite vitamin D supplementation. The BsmI bb, FokI Ff and ff genotypic variants of VDR can be considered as risk factors for the occurrence of osteoporosis in these children.

Vitamin D receptor FokI polymorphism and the risks of colorectal cancer, inflammatory bowel disease, and colorectal adenoma

Based on an inverse association between vitamin D levels and the risks of colorectal diseases, a functional start codon polymorphism in the vitamin D receptor (VDR) gene is speculated to affect the risks for these diseases. To validate this hypothesis, we first conducted a case-control study of 695 colorectal cancer patients and 1,397 controls. The association of VDR FokI polymorphism with colorectal cancer risk was analyzed using a logistic regression model. In the present case-control study, compared to the F allele, the f allele seemed to be associated with lower risks of colon cancer and advanced colorectal cancer. Additionally, a meta-analysis of 27 studies was conducted to combine findings from previous studies investigating the association of FokI polymorphism with colorectal disease using a random effects model. In the present meta-analysis, the f allele was positively associated with the risk of inflammatory bowel disease, including Crohn’s disease and ulcerative colitis. However, this allele was inversely associated with colon cancer and was not associated with the risk of rectal cancer or colorectal adenoma. In conclusion, the findings from this study imply that the role of VDR FokI polymorphism may differ based on the type and severity of colorectal disease.

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.

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.

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.

Association of the vitamin D receptor FokI gene polymorphism with sex- and non-sex-associated cancers: A meta-analysis

Currently higher morbidity and mortality rates are observed in cancer diseases, especially sex-dependent cancers. A positive role of endogenous vitamin D concentration in cancer diseases has been reported in many publications. Furthermore, there has been observed a relationship between serum vitamin D and testosterone concentrations in an elderly Caucasian population carrying the vitamin D receptor FokI gene polymorphism. The aim of this study was to investigate whether the vitamin D receptor FokI polymorphism is associated with cancerogenesis in sex-dependent cancers. The MEDLINE and ResearchGate databases were used to search for articles up to January 2017, and 96 articles concerning the FokI polymorphism were chosen. Odds ratios with 95% confidence intervals were used to assess the strength of associations between polymorphisms of vitamin D receptor and cancer risk in the described populations. The fixed-effects model and the DerSimonian-Laird random-effects model (with weights based on the inverse variance) were used to calculate summary odds ratios, and both within- and between-study variation were considered. Generally, the F variant reduces the risk of cancer by 4% (odds ratio = 0.96, p value = 0.0057). This effect is particularly evident in female sex-associated cancers (odds ratio = 0.96, 95% confidence interval: 0.93-0.99, p value = 0.0259), but it is not observed in non-sex-associated cancers. Polymorphism FokI is associated with breast and ovarian cancers.

Vitamin D 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.

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.

Vitamin D Receptor (VDR) Polymorphisms in Pediatric Patients Presenting With Hodgkin's Lymphoma

Vitamin D receptor (VDR) polymorphisms are found more commonly in some tumor types than in healthy individuals, suggesting that some polymorphisms (Cdx2, Fok1, Bsm1, Apa1, Taq1) contribute to tumor development. There is no previous report on VDR polymorphism in Hodgkin's lymphoma (HL) patients. VDR polymorphism patterns in 95 pediatric HL cases with 100 healthy controls were compared. No statistically significant difference was found between the patient group and control group in terms of Cdx2, Fok1, Bsm1, Apa1, and Taq1 polymorphisms (P>0.5). Our findings suggest that VDR polymorphisms may not play a role in HL development.

Association of Vitamin D Receptor Gene Polymorphisms with Colorectal Cancer in a Saudi Arabian Population

BACKGROUND

Vitamin D, causally implicated in bone diseases and human malignancies, exerts its effects through binding to the vitamin D receptor (VDR). VDR is a transcription factor modulating the expression of several genes in different pathways. Genetic variants in the VDR gene have been associated with several cancers in different population including colorectal cancer.

OBJECTIVE

To assess the association of VDR gene polymorphisms in relation with colorectal cancer (CRC) in a Saudi population.

METHODS

The polymorphisms of VDR gene (BsmI, FokI, ApaI and TaqI) were analyzed by the polymerase chain reaction amplification of segments of interest followed by Sanger sequencing. One hundred diagnosed CRC patients and 100 healthy control subjects that were age and gender matched were recruited.

RESULTS

We did not observe significant association of any of the four VDR polymorphisms with colorectal cancer risk in the overall analysis. Although not statistically significant, the AA genotype of BsmI conferred about two-fold protection against CRCs compared to the GG genotype. Stratification of the study subjects based on age and gender suggests statistically significant association of CRC with the 'C' allele of ApaI in patients >57 years of age at disease diagnosis and BsmI polymorphism in females. In addition, statistically significant differences were observed for the genotypic distributions of VDR-BsmI, ApaI and TaqI SNPs between Saudi Arabian population and several of the International HapMap project populations.

CONCLUSION

Despite the absence of correlation of the examined VDR polymorphisms with CRCs in the combined analysis, ApaI and BsmI loci are statistically significantly associated with CRC in elderly and female patients, respectively. These findings need further validation in larger cohorts prior to utilizing these SNPs as potential screening markers for colorectal cancers in Saudi population.

Vitamin D3 in cancer prevention and therapy: the nutritional issue

The action of vitamin D3, in its biological form 1α,25(OH)2vitD3 or calcitriol, may be summarized as a steroid-like hormone able to modulate basic functions of cell encompassing energy balance, stress response, mitochondria biogenesis, intracellular calcium oscillations, and replication/apoptosis mechanisms leading to cell survival. Moreover, calcitriol exerts a potent role as an innate and adaptive immune cytokine as immunity is closely related to self-maintenance through its energetic/metabolic balance and homeostasis of cell turnover. Therefore, vitamin D might be the ancestral form of survival hormones developed with calcified vertebrate bearing skeleton in order to survive far from water. This characteristic may suggest that the role of dietary vitamin D in preventing cancer is simply ancillary to the many factors playing a major role in contrasting impairment in energy balance and cell survival. Most probably, the immune role of calcitriol might be included in the maintenance, mostly by adipose tissue, of an anti-inflammatory, tolerant immune status, depending on the immune tolerance and modulation from the gut. A balance closely modulated by the leptin axis, which when impairments in metabolism occur, such as in insulin resistance or obesity, calcitriol is unable to face at this imbalance, while leptin plays a major role and cancer progression may be promoted. Furthermore, this mechanism promotes epithelial/mesenchymal transition-mediated fibrosis, leading to cancer resistance to immune control and drug action. Interestingly, this pathologic picture is triggered by deficiency in vitamin D from the diet. Therefore, a dietary habit including vitamin D sources, besides flavonoids, may ameliorate lifestyle and health span in most individuals, depending on their genetic background.

Differential antitumor effects of vitamin D analogues on colorectal carcinoma in culture

Colorectal cancer (CRC) is an emerging global problem with the rapid increase in its incidence being associated with an unhealthy lifestyle. Epidemiological studies have shown that decreased levels of vitamin D3 significantly increases the risk of CRC. Furthermore, negative effects of vitamin D3 deficiency can be compensated by appropriate supplementation. Vitamin D3 was shown to inhibit growth and induce differentiation of cancer cells, however, excessive vitamin D3 intake leads to hypercalcemia. Thus, development of efficient vitamin D3 analogues with limited impact on calcium homeostasis is an important scientific and clinically relevant task. The aims of the present study were to compare the antiproliferative potential of classic vitamin D3 metabolites (1α,25(OH)2D3 and 25(OH)D3) with selected low calcemic analogues (calcipotriol and 20(OH)D3) on CRC cell lines and to investigate the expression of vitamin D-related genes in CRC cell lines and clinical samples. Vitamin D3 analogues exerted anti-proliferative effects on all CRC cell lines tested. Calcipotriol proved to be as potent as 1α,25(OH)2D3 and had more efficacy than 20-hydroxyvitamin D3. In addition, the analogs tested effectively inhibited the formation of colonies in Matrigel. The expression of genes involved in 1α,25(OH)2D3 signaling and metabolism varied in cell lines analysed, which explains in part their different sensitivities to the various analogues. In CRC biopsies, there was decreased VDR expression in tumor samples in comparison to the surgical margin and healthy colon samples (p<0.01). The present study indicates that vitamin D3 analogues which have low calcemic activity, such as calcipotriol or 20(OH)D3, are very promising candidates for CRC therapy. Moreover, expression profiling of vitamin D-related genes is likely to be a powerful tool in the planning of anticancer therapy. Decreased levels of VDR and increased CYP24A1 expression in clinical samples underline the importance of deregulation of vitamin D pathways in the development of CRC.