Association of and gene haplotypes with the development of radiation-induced fibrosis in patients with nasopharyngeal carcinoma.

Radiation-induced fibrosis is one of the late complications of radiotherapy (RT) for nasopharyngeal carcinoma (NPC). The aim of this study was to investigate the association between X-ray repair cross-complementing protein 1 and 3 ( and , respectively) gene haplotypes and radiation-induced fibrosis in NPC patients. Genomic DNA was extracted from blood samples of 120 NPC patients previously treated with RT. In total, 12 tag single-nucleotide polymorphisms (SNPs) were selected from the and genes and were genotyped using restriction fragment length polymorphism analysis or unlabeled probe melting analysis. Single-marker and haplotype analyses were performed using multivariate logistic regression analysis. The functional variant rs861539 of may be associated with radiation-induced fibrosis [asymptotic P-value (P)<0.05]. No significant association was observed between radiation-induced fibrosis and any of the tag SNPs of and in either single-marker or haplotype analysis after 10,000 permutations [empirical P-value (P)>0.05]. Our preliminary results indicated that the rs861539 variant of may be associated with an increased risk of radiation-induced fibrosis; however, a large-scale study is required to confirm this result.