"Findings from genome-wide association studies (GWAS), together with analyses of specific candidate polymorphisms [gene variations], have identified a number of variants that are definitely or probably associated with breast cancer risk. There is also increasing evidence that some genetic factors have different effects on different subtypes of breast cancer," the authors write.

Gillian K. Reeves, Ph.D., of the Cancer Epidemiology Unit, University of Oxford, U.K., and colleagues conducted a study to analyze breast cancer risk, overall and by tumor subtype, in relation to 14 individual single-nucleotide polymorphisms (SNPs;) and a polygenic (relating to an inheritable character that is controlled by several genes at once) risk score. The study included 10,306 women with breast cancer (average age at diagnosis, 58 years) and 10,393 women without breast cancer, who in 2005-2008 provided blood samples for genotyping. The researchers estimated the per-allele odds ratio (OR) for individual SNPs and the cumulative incidence of breast cancer to age 70 years in relation to a polygenic risk score based on the 4, 7, or 10 SNPs most strongly associated with risk.

The researchers found that the odds ratios for breast cancer were greatest for the SNPs FGFR2-rs2981582 and TNRC9-rs3803662 and, for these 2 SNPs, were significantly greater for estrogen receptor (ER)-positive than for ER-negative disease, both in the data of this study and in meta-analyses of other published data. The next strongest association was for 2q-rs13387042, for which the per-allele OR was significantly greater for bilateral than unilateral disease and for lobular than ductal tumors.

(ScienceDaily)

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