MTHFR and breast cancer: Interestingly, in the subgroup analysis according to family history, the MTHFR rs1801133 showed a strong association with familial BC in almost all genetic models (heterozygote, OR: 4.64, 95% CI: 2.18–9.86, p = 6.8.10− 5; homozygote: OR: 4.64, 95% CI: 1.73–12.42, p = 0.002; dominant: OR: 4.64, 95% CI: 2.33–9.21, p < 10− 4; over-dominant: OR: 3.11, 95% CI: 1.55–6.24, p = 0.001 and log-additive: OR: 2.61, 95% CI: 1.60–4.25, p < 10− 4).