Association Between Genetic Polymorphisms In The DNA Double-strand Break Repair Genes Ku70and Ku80and Radiation-induced Acute Oral Mucositis In Patients With Nasopharyngeal Cancer

Objective: To investigate the association between polymorphisms in DNA repair genesKu70(c.-1310C>G, c.1781G>T) as well as Ku80(c.2099-2408G>A, c.*841G>A) and theoccurrence of radiation-induced normal tissue complications of nasopharyngeal cancer(NPC) in Chinese population.Methods and Materials: The study population consisted of120radiation therapy(RT)-treated nasopharyngeal cancer patients. RT-induced mucositis was scored using theCommon Terminology Criteria (CTC) for Adverse Events v.3.0scale. The population wasdivided into a CTC0-2and CTC3+group for the analysis of acute mucositis. Genotypeswere determined by polymerase chain reaction combined with restriction fragment lengthpolymorphism ((PCR-RFLP) technique. Logistic regression analysis was employed toassess the association between these SNPs and the risk in development of acute mucositis,adjusting for multiple confounding factors.Results: Concurrent radiochemotherapy (CRT) was signifcantly associated with thedevelopment of mucositis, and this parameter was considered confounding factor in ouranalyses. Patients carrying TT genotype in Ku70c.1781G>T have a significant lower riskfor the development of RT-induced mucositis (adjusted OR=0.312,95%CI:0.125-0.784,P=0.013). Mucositis occurred in a relative later period during radiotherapy among theindividuals carrying TT geneotype (P<0.05). No association was found between Ku70 (c.-1310C>G) as well as Ku80(c.2099-2408G>A, Ku80c.*841G>A) and the developmentof RT-induced mucositis.Conclusions: Our results provide preliminary evidence that the TT genotype in Ku70c.1781G>T seems to protect against RT-induced severe mucositis in ChineseNasopharyngeal cancer patients.