Only 5 out of 9 GWAS breast cancer loci were found to be significantly associated with breast cancer in Tunisians: The rs1219648 (G vs. A allele: OR = 1.36, P = 1 × 10(-3)) and rs2981582 (A vs. G allele: OR = 1.55, P = 3 × 10(-6)) of FGFR2 gene; the rs8051542 of the TNRC9 gene (T vs. C allele: OR = 1.40, P = 4 × 10(-4)); the rs889312 of the MAP3K1 gene (C vs. A allele: OR = 1.33, P = 3 × 10(-3)) and the rs13281615 located on 8q24 (G vs. A allele: OR = 1.21, P = 0.03).
Four SNPs mapped to 10q26.13/FGFR2 were associated with increased breast cancer risk via an additive model with per-allelic risks (95 % CI) of 1.26 (1.12-1.43) at rs1219648, 1.22 (1.07-1.38) at rs2981582, 1.21 (1.07-1.36) at rs2981579, and 1.18 (1.04-1.35) at rs11200014.
To investigate this inconsistency, we performed a meta-analysis of 37 studies involving a total of 288,142 subjects for rs2981582, rs1219648, and rs2420946 polymorphism of the FGFR2 gene to evaluate the effect of FGFR2 on genetic susceptibility for BC.
In the haplotype analysis, the FGFR2 rs2981582 T / rs2420946 T / rs1219648 G haplotype (ht2) was associated with a significantly increased BC risk compared with the rs2981582 C / rs2420946 C / rs1219648 A haplotype in familial BC and in non-familial early-onset BC (OR = 1.32, 95 % CI 1.06-1.65, P = 0.012; OR = 1.46, 95 % CI 1.11-1.91, P = 0.004, respectively).
To examine whether these variants contribute to risk of radiation-associated breast cancer in HL, we analyzed 2 independent case-control series, from the United Kingdom and The Netherlands, totaling 693 HL patients, 232 with breast cancer and 461 without. rs1219648, which annotates the FGFR2 gene, was associated with risk in both series (combined per-allele odds ratio = 1.59, 95% confidence interval: 1.26-2.02; P = .000111).
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.
The FGFR2-breast cancer association was modified by smoking status, with increased risk for former and current smokers compared to never smokers; former/current smokers carrying two copies of the rs1219648 minor allele were at highest risk with a crude OR (95% confidence interval) of 2.11 (1.52-2.92) compared to never smokers with nors1219648 variant alleles.
FGFR2 haplotypes based upon rs11200014, rs2981579, rs1219648 and rs2420946 were associated with increased risk of breast cancer, including the GTGT haplotype in AAs [OR = 1.27, 95% confidence interval (CI) 1.04-1.56] and younger women of either race [OR = 1.35, 95% CI 1.02-1.78) and the ATGT haplotype in Whites (OR = 1.30, 95% CI 1.15-1.46).
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.