title: Significance of XRCC1 Codon399 polymorphisms in Chinese patients with locally advanced nasopharyngeal carcinoma treated with radiation therapy.
abstract: OBJECTIVE
  Little is known about the relationship between XRCC1 Codon399 polymorphisms and radiotherapy (RT) outcomes in patients with nasopharyngeal carcinoma (NPC). We aimed to investigate whether XRCC1 Codon399 polymorphisms were correlated to treatment efficacy and normal tissue toxicity in Chinese patients with locally advanced NPC after RT.
  
  
  METHODS
  Sixty eligible patients with NPC stage III-IVa were recruited. Patients received definitive RT, 66-76 Gy. One cycle neoadjuvant chemotherapy with docetaxel and cisplatin regimen was used before RT, two or three cycles for concurrent chemo-RT followed by two to four cycles adjuvant chemotherapy with the same regimen. Before the treatment, XRCC1 Codon399 polymorphisms were determined by polymerase chain reaction based ligase detection reaction methods.
  
  
  RESULTS
  Six of 60 NPC patients were homozygous for XRCC1 Codon399 Gln/Gln and 35% were heterozygous. The expressions of genotypes were unrelated to gender, age, clinical stage, T stage or N stage. Codon399 Gln/Gln allele correlated with a higher medium-term tumor regression ratio after RT for primary nasopharyngeal neoplasm and metastatic lymph nodes (>80% vs 40-60%, P < 0.01). Compared with other two genotypes, patients with XRCC1 Codon399 Gln/Gln allele were more likely to obtain complete remission of tumor (100% vs 76 and 67%, P > 0.05). No correlation between XRCC1 Codon399 polymorphisms and acute or late radiation-induced injury of normal tissues was observed.
  
  
  CONCLUSIONS
  The XRCC1 Codon399 Gln/Gln allele may be associated with better tumor regression, and is suggested as a promising predictive factor for outcome for locally advanced NPC. Further study with larger samples and long-time follow-up is needed for accurate assessment.
authors.affiliation: Department of Radiation Oncology, The first Affiliated Hospital of Soochow University, Suzhou, China.|School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zhai
authors.affiliation: Department of Radiation Oncology, Suzhou Municipal Hospital (East Branch), Suzhou, China.
authors.forename: Qun-Chao
authors.initials: QC
authors.lastname: Hu
authors.affiliation: Department of Radiation Oncology, Suzhou Municipal Hospital (East Branch), Suzhou, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Gu
authors.affiliation: Department of Radiation Oncology, The first Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, The first Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Jun-Ning
authors.initials: JN
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, The first Affiliated Hospital of Soochow University, Suzhou, China.|Department of Nuclear Medicine, The first Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Wu
mesh_terms: D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D044466:Asian People / Q000235:genetics; D002277:Carcinoma; D059248:Chemoradiotherapy / Q000379:methods; D017024:Chemotherapy, Adjuvant / Q000379:methods; D002945:Cisplatin / Q000008:administration & dosage; D004268:DNA-Binding Proteins / Q000235:genetics*; D000077143:Docetaxel; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000532:radiotherapy*; D020360:Neoadjuvant Therapy / Q000379:methods; D020641:Polymorphism, Single Nucleotide; D011836:Radiation Tolerance / Q000235:genetics*; D043823:Taxoids / Q000008:administration & dosage; D016896:Treatment Outcome; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; D043823:Taxoids; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D000077143:Docetaxel; D002945:Cisplatin
keywords: XRCC1 Codon399 polymorphisms; locally advanced nasopharyngeal carcinoma; radiation therapy