Effect Of The XRCC1 Single Nucleotide Polymorphisms Of Radiotherapy In Patients Locally Advanced Nasopharyngeal Carcinoma

Objective:We detect the codon194 and codon399 single nucleotide polymorphisms (SNP) within X-ray crisscross complementary repair gene 1 (X-ray repair cross complementing-1 gene XRCC1) in locally advanced nasopharyngeal carcinoma and observ the near future curative effect of radiotherapy for patients with different genotypes to analyze the relevance between the different genotypes with the skin and oral mucosa radiation reaction.Methods:We collected 114 cases of patients who were pathologically diagnosed with nasopharyngeal poorly differentiated squamous carcinoma in the Fourth Affiliated Hospital of Guangxi Medical University from September 01, 2012 to June 31,2014. Extract venous blood before radiotherapy and extract genome DNA in blood, then use polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology to detect the codon194 and codon399 genotype in peripheral blood DNA XRCC1 in nasopharyngeal carcinoma patients. The clinical efficacy of radiotherapy of patients was evaluated after 3 months in accordance with RECIST 1.1 standard, along with skin and mucous membrane damage during radiotherapy.Results:Three months after the patient’s treatment, CR:99 cases(86.8%), PR: 15 cases(13.2%), SD:0(0%), PD:0(0%). The CR rate of short-term efficacy of radiotherapy of Arg-genotype(namely Arg/Arg and Arg/Trp) carriers has improved compared to carriers with no Arg genotype(Trp/Trp),which has statistical significance. (OR=5.938,95%CI:1.183-29.790,P=0.047). There are no obvious statistical differences between the XRCC1 codon 399 SNP and the short-term efficacy of patient’s radiotherapy. As to the side effects, there are 105 cases(92.1%) in which radiation dermatitis with grade 1-2 occur and 9 cases(7.9%) with grade 3. There are 93 cases (81.6%) in which side effects of oral mucositis with grade 1-2 occur and 21 cases(18.4%) with grade 3. There are no side effects with or above grade 4. There are no obvious differences between XRCC1 codon194 SNP and the side effects of radiation dermatitis and oral mucositis. And there are no significant correlation between XRCC1 codon399 SNP and the side effects of oral mucositis. There are 6 cases(5.3%) among the XRCClcodon 399 Arg/ Gln genotype carriers in which radiation dermatitis with grade 3 occur and one case(0.8%) among Arg/Arg genotype carriers,which indicates statistical significance (OR=8.634,95%CI:1.002-74.434,P=0.042)Conclusion:1.XRCC1 codon 194 SNP is possible to become predictor of the short-term efficacy of nasopharyngeal carcinoma radiotherapy.2. XRCC1 codon 399 SNP is possible to become predictor which can predict the degree of radiation dermatitis among nasopharyngeal carcinoma patients.