No Association Between Genetic Polymorphisms in NAD(P)H Oxidase p22^phox and Paraoxonase 1 and Colorectal Cancer Risk

Abstract

Background: Impaired metabolism of ingested toxic or carcinogenic compounds is a postulated mechanism underlying colorectal cancer (CRC). Furthermore, it is suggested that reactive oxygen species (ROS) may play a role in human cancer development. Polymorphic variations in NAD(P)H oxidase p22^phox and paraoxonase 1 (PON1) enzyme activities may alter superoxide production or the rate of chemical metabolism, respectively, and this may influence the risk for CRC. Therefore, this study was designed to determine whether the distribution of polymorphisms in NAD(P)H oxidase p22^phox and PON1 genes was different in sporadic CRC patients versus healthy controls. Materials and Methods: The study participants (365 cases and 354 controls) were all of Caucasian origin. NAD(P)H oxidase p22^phox H72Y, and PON1 L55M and Q192R polymorphisms were genotyped by polymerase chain reaction, eventually followed by restriction-fragment-length-polymorphism analyses. Results: Comparison of CRC patients and controls revealed no significant differences in genotype distributions or allele frequencies for polymorphisms in the NAD(P)H oxidase p22^phox and PON1 genes. Investigation of potential associations between the variant NAD(P)H oxidase p22^phox or PON1 alleles and the clinical characteristics, tumour location or tumour stage, also did not reveal statistically significant associations. Conclusion: Variant genotypes of NAD(P)H oxidase p22^phox and PON1 do not contribute to the susceptibility to CRC.