Mohammad Ali Esmaili - Department of Hematology, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
Ahmad Kazemi - Department of Hematology, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
Mohammad Faranoush - Pediatric Growth and Development Research Center, Institute of Endocrinology and Metabolism, Iran University of Medical Sciences, Tehran, Iran|Mahak Hematology Oncology Research Center (MAHAK-HORC), Mahak Hospital, Shahid Beheshti University
Hakan Mellstedt - Department of Oncology-Pathology, Immune and Gene Therapy Lab, Cancer Center Karolinska (CCK), Karolinska University Hospital Solna and Karolinska Institute, Stockholm ۱۷۱۷۶, Sweden

Objective(s): The current study aimed to investigate the relationship of genetic polymorphism and plasma methotrexate (MTX) levels, toxicity experience and event free survival (EFS) in pediatric acute lymphoblastic leukemia (ALL). Materials and Methods: The study included 74 ALL patients. Polymerase chain reaction and genotyping of methylene tetrahydrofolate reductase (MTHFR) rs1801133, MTHFR rs1801131, ATP-binding cassette superfamily B1 (ABCB1) rs1045642, ATP-binding cassette superfamily G2 (ABCG2) rs2231142 and solute carrier 19A1 (SLC19A1) rs1051266 genetic variations were performed. The plasma MTX levels were investigated at 48 hr after the first dose of MTX infusion.Results: MTHFR rs1801133 TT genotype, ABCBa1 rs1045642 CT genotype and ABCG2 rs2231142 CA genotype revealed a statistically significant association with the MTX plasma levels (P<0.01, P<0.05, P<0.05, respectively). The MTHFR rs1801133 TT genotype had a statistically significant association with hematopoietic toxicity (P<0.01) and interventions (P<0.05). The MTHFR rs1801131 AC genotype was related to the decreased hepatic toxicity (P<0.05). The SLC19A1 rs 1051266 GA genotype was related to the increased hepatic toxicity (P<0.05). Only the ABCB1 rs1045642 CT and TT genotypes had a statistically significant correlation with EFS (P<0.05, P<0.05, respectively).   Conclusion: Our findings showed that genetic polymorphism could be associated with plasma MTX levels, toxicity experienced and EFS in Iranian pediatric ALL.   

ABCB1, ABCG2, Genetic polymorphism, Genotype, Methotrexate, MTHFR, Pediatric acute lymphoblastic- leukemia, SLC19A1