Vitamin D status, receptor gene BsmI (A/G) polymorphism and breast cancer in a group of Egyptian females

Associations of vitamin D receptor encoding gene variants with premenopausal breast cancer risk

OBJECTIVE

This study evaluates whether vitamin D receptor (VDR) gene variations are associated with premenopausal breast cancer in Pakistani cohorts.

METHODS

Genomic DNA was isolated from 228 breast cancer patients and 500 non-cancer controls. Six polymorphic variants (rs11568820, rs4516035, rs2228570, rs1544410, rs7975232, rs731236) of the VDR gene were genotyped using PCR-RFLP analysis. All statistical analysis was carried out on IBM-SPSS 23 at p-value <.05. Chi-square test and odds ratios (ORs) along with 95% confidence interval (CIs) were applied to evaluate the relationship between VDR gene polymorphisms and breast cancer.

RESULTS

Results showed that the A/A genotype of EcoRV (OR = 2.125, 95% CI = 1.024 to 4.412) and the A/a genotype of Apa1 (OR = 6.094, 95%CI = 4.111 to 9.033) gene polymorphism had an increased risk of premenopausal breast cancer. No associations of the Bsm1 and Taq1 polymorphisms were observed in premenopausal women. Moreover, the Cdx2 GG (OR = 0.34, 95%CI = 0.192-0.602) genotype had a significant protective effect on breast cancer. However, strong LD was existed between Bsm1/Taq1 (D' = 0.757, CI = 0.67-0.82) and Apa1/Taq1 (D' = 0.695, CI = 0.6-0.77). Haplotype analysis showed no association between premenopausal breast cancer and VDR haplotypes.

CONCLUSION

These analyses indicates that the VDR EcoRV A/A and Apa1 A/a genotypes may be risk factors for breast cancer development among premenopausal women.

Association of Vitamin D receptor gene variations with Gastric cancer risk in Kashmiri population

Vitamin D receptor (VDR) mediates cellular processes like cell cycle arrest and apoptosis which effect cancer susceptibility. VDR single nucleotide polymorphisms (SNPs) have a significant influence on functioning of VDR protein and subsequently contribute to the risk of cancer occurrence and progression. The present case-control study was carried out between 2016 and 2020 to investigate the association of VDR BsmI/ApaITaqI SNPs with Gastric Cancer (GC) risk in ethnic Kashmiri population not only for establishing a molecular marker for GC but also to facilitate the outcomes of personalized medicine in future. The polymorphisms of BsmI and ApaI of the VDR gene were evaluated using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism followed by Di-Deoxy Sanger sequencing in 143 GC cases and 150 controls. The mean age (in years) was 53.5 ± 7.92 and 51.2 ± 8.25 and mean Body mass index was 22.68 ± 4.27 kg/m² and 23.81 ± 3.71 kg/m² for cases and controls respectively. The mean CEA levels of GC cases was 40.2 ± 10.9 ng/ml. Genotypic distribution of VDR BsmI differed significantly between GC cases and controls (GG vs GA + AA; adjusted P = 0.014) and followed dominant mode of inheritence. Stratification of VDR BsmI revealed that frequency of variant genotype (GA + AA) was significantly higher in Preobese GC cases (P = 0.001), GC patients consuming < 5 cups of salt tea/day (P < 0.0001) and with no family history of gastrointestinal cancer (P = 0.014) compared to healthy controls. ATC haplotype associated with high GC risk. In conclusion, our study suggests that VDR BsmI SNP has a significant association with increased risk of GC especially in preobese population and BsmI/ApaITaqI SNPs significantly decreased the overall survival in GC patients of Kashmiri population.

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.

Clinical Significance of Analysis of Vitamin D Status in Various Diseases

Vitamin D plays a role not only in the proper functioning of the skeletal system and the calcium-phosphate equilibrium, but also in the immune system, the cardiovascular system and the growth and division of cells. Although numerous studies have reported on the analysis of vitamin D status in various groups of patients, the clinical significance of measurements of vitamin D forms and metabolites remains ambiguous. This article reviews the reports analyzing the status of vitamin D in various chronic states. Particular attention is given to factors affecting measurement of vitamin D forms and metabolites. Relevant papers published during recent years were identified by an extensive PubMed search using appropriate keywords. Measurement of vitamin D status proved to be a useful tool in diagnosis and progression of metabolic syndrome, neurological disorders and cancer. High performance liquid chromatography coupled with tandem mass spectrometry has become the preferred method for analyzing the various forms and metabolites of vitamin D in biological fluids. Factors influencing vitamin D concentration, including socio-demographic and biochemical factors as well as the genetic polymorphism of the vitamin D receptor, along with vitamin D transporters and enzymes participating in vitamin D metabolism should be considered as potential confounders of the interpretation of plasma total 25(OH)D concentrations.

Vitamin D Status and Association of VDR Genetic Polymorphism to Risk of Breast Cancer in Ethiopia

Emerging evidence associates vitamin D deficiency and vitamin D receptor (VDR) genetic variations with risk for breast cancer. This study investigated the prevalence of vitamin D deficiency and its association with tumor characteristics and the implications of VDR genetic variations for risk of breast cancer in Ethiopia. This unmatched case–control study involved 392 female breast cancer patients and 193 controls. The plasma 25-hydroxyvitamin D (25(OH)D₃) level was quantified in chemotherapy-naïve (N = 112) and tamoxifen-treated patients (N = 89). Genotyping for the VDR common variant alleles rs7975232 (ApaI), rs2228570 (FokI), and rs731236 (TaqI) was done. Eighty-six percent of the patients were vitamin D deficient (<50 nmol/L). Chemotherapy-naïve breast cancer patients had a higher prevalence of vitamin D deficiency (91.9% vs. 78.3%) compared to the tamoxifen-treated group (p < 0.001). The prevalence of severe vitamin D deficiency (<25 nmol/L) was significantly higher in chemotherapy-naïve (41.1%) than tamoxifen-treated (11.2%) patients. Vitamin D deficiency was not significantly associated with tumor characteristics or VDR genotype. The rs2228570 GG genotype was associated with increased risk of breast cancer (OR = 1.44, 95% confidence interval = 1.01−2.06). Our result indicates that rs2228570 might be a moderate risk factor for breast cancer development in the Ethiopian population. The high prevalence of severe vitamin D deficiency in treatment-naïve breast cancer patients indicates the need for nutritional supplementation of vitamin D at the time of chemotherapy initiation.

Do genetic polymorphisms of the vitamin D receptor contribute to breast/ovarian cancer? A systematic review and network meta-analysis

BACKGROUND

To identify the most suitable genetic model for detecting the risk of breast cancer (BC)/ovarian cancer (OC) in specific populations.

METHODS

Databases were searched for related studies published up to October 2017. First, VDR genetic polymorphisms were compared in patients with and without cancer. Second, a network meta-analysis was used to reveal the relation between VDR genetic polymorphisms with disease outcomes. Subgroup analyses and a meta-regression were performed according to cancer types, ethnicity and genotypic method. The study is registered in PROSPERO with an ID: CRD42017075505.

RESULTS

Forty-five studies were eligible, which included 65,754 patients and 55 clinical analyses. Of genetic models, results suggested that the recessive model with the CDX2 polymorphism predicted the risk of BC in all cases. The recessive polymorphism model with the rs2228570 (FokI) polymorphism seemed to the best predictor of BC in Caucasian patients, whereas the homozygote model with the CDX2 polymorphism appeared to best predict BC in African-American patients. The homozygote model with the rs2228570 (FokI) polymorphism model appeared to detect the risk of OC in all cases, whereas the heterozygote model with the rs1544410 (BsmI) polymorphism seemed to detect the risk of OC in Caucasian patients.

CONCLUSIONS

By detecting the risk of BC, the recessive model with the rs2228570 (FokI) polymorphism is likely the best genetic model in Caucasian patients, and the homozygote model with the CDX2 polymorphism appears to be best genetic model in African-American patients. Moreover, for detecting clinical risk of OC, heterozygote models with the rs1544410 (BsmI) polymorphism is likely the best genetic model for detecting the risk of OC in Caucasian patients.

Association of low penetrance vitamin D receptor Tru9I (rs757343) gene polymorphism with risk of premenopausal breast cancer

Objective The aim of this study was to determine whether a novel polymorphism ( Tru9I) in the low penetrance vitamin D receptor (VDR) gene is associated with risk of premenopausal breast cancer (BC). Methods This case-control study included 228 patients with BC and 503 healthy women living in Pakistan who were analyzed for the VDR Tru9I (rs757343) single nucleotide polymorphism. BC cases were histopathologically confirmed, and all healthy controls were age-matched with patients (age range, 20-45 years). DNA was extracted, and the polymerase chain reaction and restriction fragment length polymorphism assays were performed. Results The VDR Tru9I polymorphism was not significantly associated with premenopausal BC. However, the risk of BC was associated with the 'uu' genotype (odds ratio [OR], 1.141; 95% confidence interval [95% CI], 0.206-6.317). Further, mutant Tru9I was significantly associated with Grade IV carcinoma (OR, 5.36; 95% CI, 1.181-24.338). Conclusion The VDR Tru9I 'uu' genotype may increase the risk of premenopausal BC.