GSTM1 and Pancytopenia: According to the National Cancer Institute’s Dictionary of Cancer Terms, pancytopenia refers to “a condition in which there is a lower-than-normal number of red and white blood cells and platelets in the blood”.6) This case was diagnosed as pancytopenia because it met the following criteria WBC (3300/μL), Hb (11.5 g/dL), and PLT (15 × 104/μL) or less.