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

The Role of Genetic Polymorphisms in Differentiated Thyroid Cancer: A 2023 Update

Thyroid cancer is the most common endocrine malignancy, with an increasing trend in the past decades. It has a variety of different histological subtypes, the most frequent one being differentiated thyroid cancer, which refers to papillary carcinoma, the most common histological type, followed by follicular carcinoma. Associations between genetic polymorphisms and thyroid cancer have been investigated over the years and are an intriguing topic for the scientific world. To date, the results of associations of single nucleotide polymorphisms, the most common genetic variations in the genome, with thyroid cancer have been inconsistent, but many promising results could potentially influence future research toward developing new targeted therapies and new prognostic biomarkers, thus consolidating a more personalized management for these patients. This review focuses on emphasizing the existing literature data regarding genetic polymorphisms investigated for their potential association with differentiated thyroid cancer and highlights the opportunity of using genetic variations as biomarkers of diagnosis and prognosis for thyroid cancer patients.

Bacterial-Viral Interactions in Human Orodigestive and Female Genital Tract Cancers: A Summary of Epidemiologic and Laboratory Evidence

Infectious agents, including viruses, bacteria, fungi, and parasites, have been linked to pathogenesis of human cancers, whereas viruses and bacteria account for more than 99% of infection associated cancers. The human microbiome consists of not only bacteria, but also viruses and fungi. The microbiome co-residing in specific anatomic niches may modulate oncologic potentials of infectious agents in carcinogenesis. In this review, we focused on interactions between viruses and bacteria for cancers arising from the orodigestive tract and the female genital tract. We examined the interactions of these two different biological entities in the context of human carcinogenesis in the following three fashions: (1) direct interactions, (2) indirect interactions, and (3) no interaction between the two groups, but both acting on the same host carcinogenic pathways, yielding synergistic or additive effects in human cancers, e.g., head and neck cancer, liver cancer, colon cancer, gastric cancer, and cervical cancer. We discuss the progress in the current literature and summarize the mechanisms of host-viral-bacterial interactions in various human cancers. Our goal was to evaluate existing evidence and identify gaps in the knowledge for future directions in infection and cancer.

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.

Vitamin D and the insulin-like growth factor system: Implications for colorectal neoplasia

Epidemiological studies have strongly associated lower levels of vitamin D and its metabolites with an increased risk of colorectal cancer (CRC). The action of calcitriol, the active metabolite of vitamin D, is mediated by the vitamin D receptor (VDR) that is present in most tissues. In advanced CRC, VDR expression is lowered. Calcitriol has several antineoplastic effects in CRC: it promotes the G1-phase cycle arrest, lowers vascular endothelial growth factor (VEGF) synthesis and acts on tumour stromal fibroblasts to limit cell migration and angiogenesis. Hyperinsulinemia and insulin-like growth factors (IGFs) have been implicated in the pathophysiology of CRC. IGF-1 and IGFBP-3 have been the most studied components of the IGF system. Only 1% of the total serum IGF-1 is free and bioactive, and 80% of it binds to IGFBP-3. IGF-1 and its receptor IGF-1R are known to induce cell proliferation. Both IGF-1 and IGFBP-3 can favour angiogenesis by increasing the transcription of the VEGF gene. A high serum IGF-1/IGFBP-3 ratio is associated with increased risk for CRC. VDR is a transcription factor for the IGFBP-3 gene, and IGF-1 can increase calcitriol synthesis. Studies examining the effect of vitamin D treatment on serum IGF-1 and IGFBP-3 have not been in agreement since different populations, dosages and intervention periods have been used. New vitamin D treatment studies that examine CRC should take in account confounding factors such as obesity or VDR genotypes.

Association between Vitamin D Receptor Single-Nucleotide Polymorphisms and Colorectal Cancer in the Thai Population: A Case-Control Study

Vitamin D and its cognate intracellular nuclear receptor, namely, vitamin D receptor (VDR), are involved in the regulation of a variety of body metabolic processes, immune function, and oncogenesis. A large number of studies demonstrated the association of low vitamin D levels and variations in five common single nucleotide polymorphisms (SNPs), FokI, BsmI, Tru9I, ApaI, and TaqI, with the risk of several cancers, including colorectal cancers. However, these associations vary among different populations. This case-control study was aimed at analysing whether common single-nucleotide polymorphisms (SNPs) and haplotypes of the vitamin D receptor (VDR) gene contribute to colorectal carcinogenesis in the Thai population. We enrolled 364 Thai participants from King Chulalongkorn Memorial Hospital between 2014 and 2015. Half of the participants underwent colonoscopy and showed a normal colon without polyps (control group) and another half were newly diagnosed patients with colorectal cancer (CRC) by colonoscopy during the index period, were under treatment, or were followed up at the outpatient clinic (case group). Differences in allele and genotype frequencies of five common VDR SNPs, between the case and control groups, were the primary outcome measures. Differences in haplotype frequencies of the five SNPs between the case and control groups were the secondary outcome measures. Among the 364 participants, baseline characteristics were not significantly different between the case and control groups, except for the higher proportion of males in the CRC group. The mean vitamin D level was also not significantly different between the case and control groups (24.6 ± 9.1 vs. 25.3 ± 10.6 ng/mL, p = 0.52). None of the five VDR SNPs was associated with CRC development (p > 0.05). However, haplotype analysis of these polymorphisms demonstrated that the AGGT haplotype was associated with a decreased risk of CRC (odds ratio 0.24, 95% confidence interval 0.07-0.81, p = 0.01). The AGGT haplotype was associated with a lower risk of CRC in the Thai population. This genetic linkage might support the role of vitamin D in colorectal carcinogenesis. However, this finding requires further study within a larger population and a multivariate analysis of other established risk factors.

Medullary thyroid cancer is associated with high serum vitamin D level and polymorphism of vitamin D receptors

Background

Thyroid cancer is the most common endocrine malignancy. Studies have observed an anti-cancer effect for vitamin D and found that polymorphisms of vitamin D receptors can influence the prevalence of various cancers. The present study investigated the serum level of vitamin D and FokI, BsmI and Tru9I polymorphisms of vitamin D receptors.

Methods

Forty patients with medullary thyroid cancer and 40 healthy controls were investigated. The genomic DNA of the subjects was extracted using saturated salt/proteinase K and investigated by PCR sequencing. Serum levels of vitamin D were evaluated by ELISA. The results were analyzed in SPSS and GraphPad Prism 5 software.

Results

The genotypic and allelic frequencies of FokI and BsmI polymorphisms showed no significant differences between test and control groups. For Tru9I polymorphism, Tt genotype and t allelic frequency in the test group were significantly different from those of the control group. Also, we found Tt genotype and t allelic frequency to be significantly associated with medullary thyroid cancer (MTC) type and the agressiveness of the disease. The average serum vitamin D level was 23.32 ng/mL and 18.95 ng/mL for patients and controls, respectively, and the difference between the two groups was statistically significant. Moreover, we found high serum vitamin D level to be associated with t allelic frequency.

Conclusions

Unexpectedly, the mean serum vitamin D level of the test group was significantly higher than that of the control group. Tru9I polymorphism was found to be significantly correlated with the prevalence of medullary thyroid carcinoma.

Unveiling molecular associations of polymorphic variants of VDR gene (FokI, BsmI and ApaI) in multiple myeloma patients of Indian population

Multiple myeloma (MM) is a plasma cell malignancy frequently accompanied with skeletal co-morbidity. Vitamin D (1,25(OH)₂D) is an important mediator of skeletal homeostasis that mediates its effect by binding to vitamin D receptor (VDR), a steroid family receptor and modulates various downstream pathways. Multiple polymorphisms have been determined in VDR gene that witnessed significant association with cancer development and progression. Therefore, in this maiden study, we recruited 75 newly diagnosed MM patients and 75 control subjects. 25-hydroxy vitamin D (25(OH)D) levels were measured in all recruited study subjects. Further, PCR-RFLP was performed in DNA samples of recruited study subjects. Results demonstrated significantly decreased 25(OH)D levels in MM patients compared to controls. Additionally, decreased 25(OH)D levels in MM patients inversely associated with disease severity. Further, single nucleotide polymorphism (SNP) analysis of VDR gene showed significantly higher risk of MM disease development in Ff + ff, Aa + aa, and Bb + bb genotypes. Additionally, FokI f, ApaI a and BsmI b alleles were significantly associated with MM occurrence. In conclusion, this study provided initial evidences of association between 25(OH)D insufficiency, VDR gene polymorphism and MM development. Thus, we suggest that a study involving assessment of 25(OH)D levels and VDR gene polymorphism in large patients' cohort might substantiate their role in MM development which would further provide impetus to give 25(OH)D supplementation along with conventional chemotherapeutic agents for myeloma treatment in future.

CYP27B1 Gene Polymorphism rs10877012 in Patients Diagnosed with Colorectal Cancer

Colorectal cancer (CRC) is the third most commonly occurring cancer worldwide. Intestinal cells are CYP27B1 gene expression sites and, as a consequence, they are capable of converting pro-vitamin D into the active paracrine and autocrine forms. It was demonstrated that rs10877012 polymorphism in the CYP27B1 gene influenced the circulating vitamin D level. This provided a rationale for determining the role that this polymorphism plays in the risk of developing colon cancer. In this study, we investigated the association of rs10877012 (T/G) polymorphism in the CYP27B1 gene with CRC susceptibility. The study population (n = 325) included CRC patients (n = 106) and healthy controls (n = 219). DNA was extracted from peripheral leukocytes and analyzed for the CYP27B1 polymorphism using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. We found an association between the presence of the T allele at the polymorphic site (odds ratio (OR) = 2.94; 95% CI 1.77–4.86; p < 0.0001) and a decreased CRC incidence.

The Role of Vitamin D and Sunlight Incidence in Cancer

BACKGROUND

Vitamin D (VD) deficiency affects individuals of different ages in many countries. VD deficiency may be related to several diseases, including cancer.

OBJECTIVE

This study aimed to review the relationship between VD deficiency and cancer.

METHODS

We describe the proteins involved in cancer pathogenesis and how those proteins can be influenced by VD deficiency. We also investigated a relationship between cancer death rate and solar radiation.

RESULTS

We found an increased bladder cancer, breast cancer, colon-rectum cancer, lung cancer, oesophagus cancer, oral cancer, ovary cancer, pancreas cancer, skin cancer and stomach cancer death rate in countries with low sunlight. It was also observed that amyloid precursor protein, ryanodine receptor, mammalian target of rapamycin complex 1, and receptor for advanced glycation end products are associated with a worse prognosis in cancer. While the Klotho protein and VD receptor are associated with a better prognosis in the disease. Nfr2 is associated with both worse and better prognosis in cancer.

CONCLUSION

The literature suggests that VD deficiency might be involved in cancer progression. According to sunlight data, we can conclude that countries with low average sunlight have high cancers death rate. New studies involving transcriptional and genomic data in combination with VD measurement in long-term experiments are required to establish new relationships between VD and cancer.

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.

Influence of vitamin D on cancer risk and treatment: Why the variability?

The association between vitamin D and cancer has long been studied, but the results have been variable. Thus, there does not seem to be a consensus on whether vitamin D has a beneficial anti-cancer effect. This review not only summarizes the association between vitamin D and cancer risk and results of clinical trials involving vitamin D, but explores some of the reasons that contribute to the variability of study outcomes. Highlighted are single nucleotide polymorphisms (SNPs) that contribute to variability in the efficacy of vitamin D supplementation. Understanding these differences can personalize approaches to optimize the effectiveness of vitamin D in limiting cancer risk.