GSTM1 and acute lymphoblastic leukemia: A 9-year-old girl with acute lymphocytic leukemia (ALL) complicated with disease relapse after about 32 months of the induction chemotherapy was admitted with pancytopenia (total WBC count 1800/mm3, Hb 9.6 gr/dL, and platelet 9000/ mm3) on 20 November 2020.