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Polymorphisms in the estrogen receptor alpha gene, mammographic density and breast cancer risk
The PvuII and the XbaI
polymorphism in the estrogen receptor alpha gene (ESR1, 6q25) have
been related to an increased breast cancer risk, but the results are not
fully consistent. To further elucidate this relation, we examined these
polymorphisms in relation to mammographic density, a measure of dense
tissue in the breast. Fat tissue is translucent and appears dark on a
mammogram, whereas connective and epithelial tissue are dense and appear
white. The proportion of dense tissue in the breast is referred to as
mammographic density. High mammographic density has been associated with a
4 to 6-fold increase in breast cancer risk. We performed genotyping and assessed
mammographic density for 620 women from the Prospect-EPIC cohort. Mean
mammographic density was compared for the different PvuII
and XbaI genotypes. Mammographic density was higher in women with PvuII Pp and pp genotype (means 37% and 36%, respectively) than in those with the PP genotype (32%, p for trend=0.09). Women with the XbaI Xx and xx genotype had a higher mean mammographic density (means 36% and 37%, respectively) than those with the XX genotype (31%, p for trend < 0.01). These results suggest that the relation between ESR1 polymorphisms may affect breast cancer risk through differences in mammographic density.
Reference:
Fränzel J.B. van Duijnhoven Julius
Center for Health Sciences and Primary Care University Medical Center,
Utrecht, the Netherlands
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