Rapid analysis of XRCC1 polymorphisms using real-time polymerase chain reaction

DNA repair plays a critical role in protecting the genome from carcinogens or ionizing radiation. Three coding polymorphisms at codons 194, 280, and 399 in X-ray cross-complementing group 1 (XRCC1) DNA repair gene have been identified that may affect DNA repair and alter cancer susceptibility. In order to study their role in molecular-epidemiology studies we developed a single-step procedure for genotyping these polymorphisms using real-time polymerase chain reaction (rt-PCR) and subsequent melting curve analysis. Genotypes of 622 unrelated Caucasians without prior history of cancer were determined by real-time PCR and compared to genotypes obtained by restriction fragment length polymorphism PCR. In the population studied, the allele frequency of the XRCC1 26304 site (C-->T) of codon 194 in exon 6 was 0.065, the allele frequency of the XRCC1 27466 site (G-->A) of codon 280 in exon 9 was 0.048 and of the XRCC1 28152 site (G-->A) of codon 399 in exon 10 was 0.35. There was no disagreement between the two methods. These findings confirm the real-time fluorescence PCR method as a rapid and reliable assay for the analysis of large numbers of samples.