The polymorphism and haplotypes of XRCC1 and survival of non-small-cell lung cancer after radiotherapy

PURPOSE: The X-ray repair cross-complementing Group 1 (XRCC1) protein is involved mainly in the base excision repair of the DNA repair process. This study examined the association of 3 polymorphisms (codon 194, 280, and 399) of XRCC1 and lung cancer in terms of whether or not these polymorphisms have an effect on the survival of lung cancer patients who have received radiotherapy. METHODS AND MATERIALS: Between January 2000 and April 2004, 229 lung cancer patients with non-small-cell lung cancer in Stages I-III were enrolled. Genotyping was performed by single base primer extension assay using the SNP-IT Kit with genomic DNA samples from all patients. The haplotype of the XRCC1 polymorphisms was estimated by PHASE version 2.1. RESULTS: The patients consisted of 191 (83.4%) males and 38 (16.6%) females with a median age of 62 (range, 26-88 years). Sixty percent of the patients were included in Stage I-IIIa. The median progression-free and overall survival was 13 months and 16 months, respectively. The XRCC1 codon 194, histology, and stage were shown to be significant predictors of the progression-free survival. The 6 haplotypes among the XRCC1 polymorphisms (194, 280, and 399) were estimated by PHASE v.2.1. The patients with haplotype pairs other than the homozygous TGG haplotype pairs survived significantly longer (p = 0.04). CONCLUSIONS: Polymorphisms of XRCC1 have an effect on the survival of lung cancer patients treated with radiotherapy, and this effect seems to be more significant after the haplotype pairs are considered.