Due to many biological cell functions of vitamin D including regulation of cell survival, proliferation and differentiation, the metabolism of itself gains importance in the development of several types of cancer. This case-control study was designed to evaluate the risk of gastric cancer development in terms of VDR rs2228570 & rs731236, and VDBP rs7041 polymorphisms, and serum levels of vitamin D. The study consists of 77 gastric cancer patients and 84 healthy individuals. VDR and VDBP gene polymorphisms and vitamin D levels were determined by using PCR-RFLP and HPLC methods. The distribution of VDR or VDBP gene variants were not different in study groups. The serum level of 25-hydroxyvitamin D was significantly lower in gastric cancer patients versus controls (16 ± 6 → 11 ± 6 ng/ml) in which male patients have higher levels than females. Although the whole study population lacks normal levels of 25-hydroxyvitamin D, it was found that the risk of the development of gastric cancer was approximately fourfold higher in cases with severe vitamin D (< 10 ng/ml) deficiency. Our results indicate that VDR rs731236 & rs2228570 or VDBP rs7041 polymorphisms were not risk factors for the development of gastric cancer individually, however, lower serum levels of vitamin D may be a contributory risk for both predisposition and development of gastric cancer.
Keywords: Gastric cancer; Polymorphism; VDBP; VDR; Vitamin D.