Vitamin D receptor FokI and BsmI gene polymorphism and its association with grade and stage of renal cell carcinoma in North Indian population

Abstract

Vitamin D exerts its activity through binding to the high-affinity nuclear vitamin D receptor (VDR), and majority of genetic studies have primarily focused on variation within this gene. Therefore, analysis of genetic variation in VDR genes may provide insight into the role of vitamin D in renal cell carcinoma (RCC) etiology in our study population. This study investigated whether VDR gene polymorphisms were associated with increased risk and prognosis of RCC in the North Indian population. Genotyping of two polymorphic sites (FokI and BsmI) in the VDR gene of 196 RCC cases and 250 healthy controls was performed via PCR-RFLP. The frequency of homozygous genotype FF was 31.6%, heterozygous Ff was 48.0%, and homozygous ff was 20.4% in cases, whereas in controls it was 45.6%, 39.2%, and 15.2%, respectively; thus, there was a significant difference between the two groups (p (Trend) = 0.011) in the univariate model. The frequencies of the BB, Bb, and bb genotypes were 25.5%, 44.9% and 29.6% in cases, respectively, while in controls it was 33.2%, 52.0% and 14.8%, respectively; thus, there was a significant difference between the two groups (p (Trend) = 0.001) in the univariate model. The two high-risk genotype ff of FokI and bb of BsmI of VDR showed a cumulative 1.87-fold increase in risk to RCC. Moreover, the FF genotype was associated with lower pathological stage and histological grade. Our results suggest that the FokI and BsmI genotypes of VDR gene may be implicated in the pathogenesis of RCC.