Overall, significantly elevated BC risk was associated with rs2981582, rs1219648, and rs2420946 risk allele when all studies were pooled into the meta-analysis.
Three commonly studied FGFR2 polymorphisms including rs1219648 (A > G), rs2420946 (C > T), and rs2981582 (C > T) were selected to explore their association with risk of development of breast cancer by meta-analysis of published case-control studies.
In the context of a nationwide, population-based case-control study in Sweden, we retrieved recorded birth weight for 693 breast cancer cases and 747 control women who were also genotyped for most or all of the seven recently documented breast cancer susceptibility SNPs: rs2981582, rs12443621, rs8051542, rs3803662, rs889312, rs13281615, and rs3817198.
The known breast cancer SNPs rs13281615, rs2981582 and rs3803662 were confirmed as associated with breast cancer risk (P (allelic test) = 1.8 x 10(-2), OR = 1.17; P (allelic test) = 2.2 x 10(-3), OR = 1.22; P (allelic test) = 5.1 x 10(-2), OR = 1.15, respectively) in the West of Ireland cohort.
FGFR2 rs1219648 and rs2981582 genotypes were significantly associated with breast cancer in EA only in estrogen receptor-positive (ER+), progesterone receptor-positive (PR+) and HER2/Neu-negative (HER2-) tumors.
We genotyped 13 single nucleotide polymorphisms (SNPs) densely covering a 27 kb region within intron 2 of FGFR2 including two SNPs (rs2981582 and rs1219648) significantly associated with breast cancer and a total 40 tagSNPs across 150 kb of the FGFR2 gene.
The minor alleles of SNP rs2981582 and rs889312 were each associated with increased breast cancer risk in BRCA2 mutation carriers (per-allele hazard ratio [HR] = 1.32, 95% CI: 1.20-1.45, p(trend) = 1.7 x 10(-8) and HR = 1.12, 95% CI: 1.02-1.24, p(trend) = 0.02) but not in BRCA1 carriers. rs3803662 was associated with increased breast cancer risk in both BRCA1 and BRCA2 mutation carriers (per-allele HR = 1.13, 95% CI: 1.06-1.20, p(trend) = 5 x 10(-5) in BRCA1 and BRCA2 combined).
We also noted a correlation between the number of minor alleles of rs2981582 in FGFR2 and the average number of first-degree and second-degree relatives with breast cancer and/or ovarian cancer (P = 0.05).