Vitamin D receptor gene polymorphisms and breast cancer risk.
OBJECTIVE
The steroid hormone 1,25-dihydroxyvitamin D3 is thought to protect against breast cancer. The actions of 1,25-dihydroxyvitamin D3 are mediated via the vitamin D receptor (VDR), and a number of polymorphisms in the VDR gene have been identified. These result in distinct genotypes, some of which may alter susceptibility to breast cancer. We have investigated whether specific VDR gene polymorphisms are associated with breast cancer risk in a United Kingdom Caucasian population.


METHODS
In a retrospective case-control study, female breast cancer patients (n = 398) and control women (n = 427) were recruited, and three VDR polymorphisms were determined.


RESULTS
The 3' VDR polymorphisms BsmI and variable-length poly(adenylate) sequence were both significantly associated with breast cancer risk; odds ratios (adjusted for age menopausal status and hormone replacement therapy usage) for bb genotype versus BB genotype = 1.92 (95% confidence interval, 1.20-3.10; P < 0.01) and for LL versus SS = 1.94 (95% confidence interval, 1.20-3.14; P < 0.01). A 5' VDR gene variant, FokI, was not associated with breast cancer risk when analyzed in isolation (P > 0.05). However, FokI did modulate the increased risk associated with the bb/LL genotype such that possession of one or more F alleles together with the bb/LL genotype augmented breast cancer risk. Furthermore, the highest proportion of bb and FFLL/FfLL genotypes occurred in women with metastatic breast cancer.


CONCLUSIONS
VDR polymorphisms are associated with breast cancer risk and may be associated with disease progression. Additional investigations into how different genotypes may affect the functional mechanisms of the VDR will provide a better strategy for identifying women at risk of breast cancer and for developing improved treatments.
Guy
Michelle
M
Department of Cellular and Molecular Medicine, St. George's Hospital Medical School, London, United Kingdom.
Lowe
Lorraine C
LC
Bretherton-Watt
Deborah
D
Mansi
Janine L
JL
Peckitt
Clare
C
Bliss
Judith
J
Wilson
Rosalind Given
RG
Thomas
Valerie
V
Colston
Kay W
KW
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D018167:Receptors, Calcitriol / Q000235:genetics*; D015183:Restriction Mapping; D012189:Retrospective Studies; D018570:Risk Assessment
D018167:Receptors, Calcitriol