MTHFR and breast cancer: Gene mutations in OCM pathway including methylenetetrahydrofolate reductase (MTHFR) 677 (rs1801133), MTHFR 1298 (rs1801131), methionine synthase (MTR) 2756 (rs1805087), methionine synthesis reductase (MTRR) 66 (rs1801394), and dihydrofolate reductase (DHFR) 19bp (rs70991108) affect the folate-mediated pathway and could subsequently result in aberrant methylation and disruption of DNA synthesis and repair, thereby increasing the risk of BC [9, 11].