Vitamin D receptor gene ApaI polymorphism is associated with susceptibility to colorectal cancer.

OBJECTIVES

The purpose of this study was to investigate vitamin D receptor (VDR) gene ApaI and TaqI polymorphisms in relation to the risk of colorectal cancer (CRC) in the Iranian population.

METHODS

Two single nucleotide polymorphisms in intron 8 (ApaI) and exon 9 (TaqI) of the VDR gene were genotyped in 160 subjects with CRC and 180 controls by use of the PCR-RFLP method.

RESULTS

The VDR ApaI genotype distribution differed significantly between subjects with CRC and controls. The ApaI "aa" genotype compared with "AA" genotype was associated with a 2.3-fold increased risk of CRC (P = 0.014; OR = 2.25, 95% CI = 1.18-4.28) and the difference remained significant after adjustment for age, BMI, sex, and smoking status (P = 0.014; OR = 2.32, 95% CI = 1.19-4.54). Furthermore, the ApaI "a" allele was significantly overrepresented in subjects with CRC than controls (P = 0.014; OR = 1.48, 95% CI = 1.08-2.02).

CONCLUSIONS

These findings suggest that VDR ApaI genotype "aa" is associated with increased risk of CRC in the Iranian population. However, these data remain to be confirmed in larger studies and in other populations.