Vitamin D receptor gene haplotypes and polymorphisms and risk of breast cancer: a nested case-control study.
BACKGROUND
Observational and experimental studies suggest that vitamin D may influence breast cancer etiology. Most known effects of vitamin D are mediated via the vitamin D receptor (VDR). Few polymorphisms in the VDR gene have been well studied in relation to breast cancer risk and results have been inconsistent.


METHODS
We investigated VDR polymorphisms and haplotypes in relation to breast cancer risk by genotyping 26 single nucleotide polymorphisms (SNP) that (i) had known/suspected impact on VDR function, (ii) were tagging SNPs for the three VDR haplotype blocks among whites, or (iii) were previously associated with breast cancer risk. We estimated odds ratios (OR) and 95% confidence intervals (CI) in relation to breast cancer risk among 270 incident cases and 554 matched controls within the Agricultural Health Study cohort.


RESULTS
In individual SNP analyses, homozygous carriers of the minor allele for rs2544038 had significantly increased breast cancer risk (OR = 1.5; 95% CI: 1.0-2.5) and homozygous carriers of the minor allele for rs11168287 had significantly decreased risk (OR = 0.6; 95% CI: 0.4-1.0). Carriers of the minor allele for rs2239181 exhibited marginally significant association with risk (OR = 1.4; 95% CI: 0.9-2.0). Haplotype analyses revealed three haplotype groups (blocks "A," "B," and "C"). Haplotype GTCATTTCCTA in block B was significantly associated with reduced risk (OR = 0.5; 95% CI: 0.3-0.9).


CONCLUSIONS
These results suggest that variation in VDR may be associated with breast cancer risk.


CONCLUSIONS
Our findings may help guide future research needed to define the role of vitamin D in breast cancer prevention.
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA. Larry.Engel@unc.edu
Lawrence S
LS
Engel
Irene
I
Orlow
Camelia S
CS
Sima
Jaya
J
Satagopan
Urvi
U
Mujumdar
Pampa
P
Roy
Sarah
S
Yoo
Dale P
DP
Sandler
Michael C
MC
Alavanja
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000209:etiology / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies; D018167:Receptors, Calcitriol / Q000235:genetics*; D012306:Risk
D018167:Receptors, Calcitriol