In recent years, the Terry Fox Cancer Research group in the China Medical University and Hospital has been continuously devoted to the genotyping work of breast cancer in Taiwan, and their efforts have provided some potential predictive biomarkers such as G-1394T (rs 6869366) in XRCC4 [14], K589E (rs1047840) in EXO1 [15], G-1401T (rs828907) in XRCC5 [16], Asp312Asn (rs1799793) in XPD [17], rs189037 in ATM [18], G14713A and T29107A in CAV-1 [19], C-802G (rs14133) in CRYAB [20], C677T (rs1801133) in MTHFR [21], and G-765C (rs20417) in COX-2 [10]. The gene discussed is MTHFR; the disease is breast cancer.