Start codon polymorphisms in the vitamin D receptor and colorectal cancer risk

Abstract

The expression of the nuclear vitamin D receptor (VDR), which is involved in regulating cell growth and proliferation, may contribute to the development of colorectal cancer. Polymorphisms in the VDR gene (OMIM 601769) may influence the expression or function of the VDR protein. A population-based, case-control study of VDR start codon, intron, and exon polymorphisms, haplotypes for these polymorphisms, and the relationships between these polymorphisms and clinicopathological parameters in 190 colorectal cancer patients and 318 controls was conducted. The start codon variant VDR 27823*C/*C genotype was associated with an increased risk for colorectal cancer, while the 27823*T/*T genotype was associated with a decreased risk. In addition, the VDR 61888*G/*G genotype was associated with reduced colorectal cancer risk. The intron 8 60880G>A and exon 9 61968T>C polymorphisms were not associated with colorectal cancer risk. The VDR 27823*C-60890*G-61888*T-61968*T haplotype was associated with an increased risk of colorectal cancer, whereas the VDR 27823*T-60890*G-61888*G-61968*T haplotype was associated with a decreased risk of colorectal cancer. Moreover, the 27823*C/*C genotype was more frequently identified in patients with preoperative serum carcinoembryonic antigen (CEA) levels over 6ng/mL. These results suggest that the VDR start codon 27823*C allele may be linked to high risk for colorectal cancer, especially in a subset of colorectal cancers showing specific biological behaviors.