APEX1 rs1130409 encoding p.Asp148Glu showed redundant interaction (OR’interaction = 0.85) with the GSTT1-null genotype, but suppressive interaction (OR’interaction = 0.77) with the GSTT1-GSTM1 double-null genotype in gastric cancer susceptibility [23]. The gene discussed is GSTM1; the disease is gastric cancer.