Background and Aim: Although the functional consequences of MDR-1 polymorphisms have been the subjectof numerous studies, to the best to our knowledge, associations with clinical side effects of anticancer drugshave yet to be assessed. Our aim was to clarify any role of the C3435T polymorphism of the MDR1 gene in oralmucositis and its relation with elevated reactive oxygen species (ROS) levels, in children with acute lymphoblasticleukemia (ALL). Materials and
Methods: The distribution of the MDR-1 C3435T polymorphism in 47 patientswith ALL was determined by RFLP and compared with that of 68 healthy controls.
Results: There were noassociation in distribution of genotypes of MDR-1 C3435T polymorphism and the risk of ALL. Oral mucositiswere detected in 78.7% (n=37) of the patients and significantly related to the MDR-1 CT genotype (p=0.042), asconfirmed by logistic regression analysis.
Conclusion: Our preliminary data suggest that children carrying theCT genotype are more prone to develop oral mucositis, which might mean that the heterozygous genotype leadsto accumulation of more reactive oxygen species. Since a limited number of patients was investigated, furtherstudies are needed to confirm these findings.