Myeloperoxidase promotor polymorphism and risk of hepatoblastoma.

Myeloperoxidase (MPO) is a major enzyme found in neutrophils. Oxidation by MPO produces free radicals that demonstrate genotoxic properties. A polymorphism (G to A) within the promotor region of the MPO gene reduces transcription and expression. This polymorphism is associated with a protective effect against some cancers in adults including lung cancer. The objective of our study was to investigate the effect of this MPO polymorphism on the risk of hepatoblastoma, the most common cancer of the liver in childhood. By using PCR-SSCP, we determined the genotype at this polymorphism in 48 cases of Caucasian children with hepatoblastoma and 180 normal controls. Genotypes were confirmed by a second method using Aci I restriction enzyme restriction. We found that A allele was associated with reduced risk of hepatoblastoma of 50% (OR, 0.51; 95%CI, 0.27-0.93) and G/A or A/A genotype reduced the risk by 56% (OR, 0.44; 95%CI, 0.21-0.90). Our data suggest that A allele is a protective factor with regard to the risk of hepatoblastoma, perhaps by altering genotoxic properties of xenobiotic substances which may act as carcinogens.