The Association Between the Genetic VDR SNP c.907+75C>T and Prostate Cancer Risk Is Modified by Tanning Potential.

Abstract

Prostate cancer (PCa) is a multifactorial disease involving complex interactions between genetic and physiological/environmental factors. Vitamin D receptor (VDR) plays a role in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to PCa. Logistic regression analysis was used to assess the association of six VDR single nucleotide polymorphisms (SNPs) and factors such as tanning potential and UV sunlight exposure with PCa risk. Marginal significant interactions were found, with a 2-fold increase risk of PCa between SNP 1 (c.278-69G>A) and sunlight UV exposure [odds ratio (OR)=2.02, 95% confidence intervaI (CI)=1.036-4.36; p=0.05]; and a 4-fold increase risk of PCa between SNP 4 (c.907+75C>T) and tanning potential (OR=4.40, 95% CI=0.89-29.12; p=0.0591). In contrast, SNP 5 (rs731236, TaqI) and tanning potential interaction had a protective effect by reducing the risk of PCa by 55% (β=-0.804; OR=0.448, 95% CI=0.197-9.42; p=0.0427). SNPs 2 (rs61614328) and 6 (rs533037428) did not show any association with PCa even in the presence of UV sunlight exposure. The protective effect of SNP 4 from PCa is lost and modified by tanning potential in African Americans. This finding needs to be verified by larger studies in different ethnic populations.