The Association of Vitamin D Receptor Gene Variants (FokI and ApaI) with Gastric Cancer Susceptibility.

Background: Gastric Cancer is the fourth leading cancer worldwide and remains an important health burden due to high morbidity and mortality. The association of vitamin D receptor (VDR) with various cancer types had been investigated. Nevertheless, there are controversial results concerning the association of certain VDR gene polymorphisms with gastric cancer. 
Objectives: The present study sought to assess the levels of Vitamin D in patients with gastric cancer as compared with healthy individuals and to investigate the association of VDR gene polymorphisms (ApaI rs7975232 and Fok1 rs2228570) with risk of gastric cancer in Iraqi population of Baghdad city. 
Methodology: This case-control investigation involved 128 individuals, from them 64 patients with gastric cancer as well as 64 apparently healthy individuals. The VIDAS total (VITD) has been utilized to measure the concentrations of Vitamin D. The PCR-RFLP technique has been applied to detect the studied genetic variants. 
Results: The results of statistical analysis showed a significant (p=0.001) decrease of vitamin D in patients with Gastric cancer as compared with control group. The genetic analysis of studied variants showed that only the genotypes and alleles frequencies of FokI (rs2228570) variant demonstrated a significant difference between patients and healthy individuals, where this variant reveals a significant association with gastric cancer susceptibility, while no significant associations were found regarding ApaI (rs7975232) variant. Furthermore, the present investigation also explored the association between VDR variants and serum levels of vitamin D, the distribution of serum concentrations of vitamin D according to genotypes of FokI revealed a significant increase in vitamin D levels in both patients and controls have the genotype CC as compared with those have CT and TT; while there are no significant differences among serum levels of vitamin D distributed according to ApaI genotypes in both patients and controls. 
Conclusion: Vitamin D levels were significantly reduced in gastric cancer patients relative to healthy individuals. FokI (rs2228570) variant was linked with both vitamin D status and gastric cancer risks.