Lack of Association Between BsmI and FokI Polymorphisms of the VDR Gene and Sporadic Colorectal Cancer in a Romanian Cohort-A Preliminary Study.

Abstract

Colorectal cancer (CRC) is a major public health problem worldwide, currently ranking third in cancer incidence and second in mortality. Multiple genes and environmental factors have been involved in the complex and multifactorial process of CRC carcinogenesis. VDR is an intracellular hormone receptor expressed in both normal epithelial and cancer colon cells at various levels. Several VDR gene polymorphisms, including FokI and BsmI, have been evaluated for their possible association with CRC susceptibility. The aim of our study was to investigate these two SNPs for the first time in Romanian CRC patients. FokI (rs228570 C>T) and BsmI (rs1544410 A>G) were genotyped by real-time polymerase chain reaction (RT-PCR) in 384-well plates using specific TaqMan predesigned probes on a ViiA™ 7 RT-PCR System. A total of 441 subjects (166 CRC patients and 275 healthy controls) were included. No statistically significant difference was observed between CRC patients and controls when we compared the wild-type genotype with heterozygous and mutant genotypes for both FokI (OR 0.85, 95% CI: 0.56-1.28; OR 0.95, 95% CI: 0.51-1.79, respectively) and BsmI (OR 0.97, 95% CI: 0.63-1.49; OR 1.10, 95% CI: 0.65-1.87, respectively) or in the dominant and recessive models. Also, we compared allele frequencies, and no correlation was found. Moreover, the association between these SNPs and the tumor site, TNM stage, and histological type was examined separately, and there was no statistically significant difference. In conclusion, our study did not show any association between FokI and BsmI SNPs and CRC susceptibility in a Romanian population. Further studies including a larger number of samples are needed to improve our knowledge regarding the influence of VDR polymorphism on CRC susceptibility.