While initial blood test results before starting TAM showed mild anemia (Hb: 8.9 g/dL Grade 2), a follow-up blood test 5 months after initiating TAM revealed a significant decrease in blood cell counts (white blood cell [WBC]: 2600/μL Grade 2, neutrophil [neu]: 0.55 × 103/μL Grade 3, Hb: 7.7 g/dL Grade 2, platelet [PLT]: 13.3 × 104/μL). Here, GSTM1 is linked to anemia (phenotype).