The association between four SNPs of X-ray repair cross complementing protein 1 and the sensitivity to radiotherapy in patients with esophageal squamous cell carcinoma

Early stage diagnosis and therapeutic outcomes of esophageal squamous cell carcinoma remain poor. In order to evaluate the association between 4 single nucleotide polymorphisms (SNPs) of X-ray repair cross complementing protein 1 (XRCC1) and the sensitivity to radiotherapy in patients with esophageal squamous cell carcinoma (ESCC), the present study identified 4 SNPs of XRCC1 and evaluated the distribution of these genotypes among patients with ESCC. Venous blood samples from 175 patients with ESCC were collected and DNA was extracted. The 4 SNPs of the XRCC1 gene fragment were amplified using three primer pairs, which were sequenced. The mismatches were analyzed and identified using Basic Local Alignment Search Tool software. The sensitivity to radiotherapy was graded as effective and non-effective, according to the treatment results of the patients. The present study successfully amplified and sequenced 4 SNPs of XRCC1 in 112 out of the 175 patients with ESCC. The effective response rate of radiotherapy was 84.8% among the 112 patients. The effective response rate of patients with no mutation in the SNPs was 74.3%, and the rate increased to 89.6% in patients that had >= 1 mutation out of the 4 SNPs (chi(2)=4.389; P=0.036). For G28152A and G28152A mutations the effective response rate of patients was 91.2% (chi(2)=4.014; P=0.045) and 91.5% (chi(2)=4.451; P=0.035), respectively, which was significantly different compared to patients with no mutation (P=0.045 and P=0.035, respectively). The present results suggest that the 4 SNPs of XRCC1 are associated with the effective response rate of radiotherapy in patients with ESCC. The mutation of SNP G28152A was particularly important and may be a potential genomic predictor for radiotherapy sensitivity in patients with ESCC.