title: Variant haplotypes at XRCC1 and risk of oral leukoplakia in HPV non-infected samples.
abstract: BACKGROUND
  One of the mechanisms in human papillomavirus (HPV)-related carcinogenesis is inhibition of DNA repair by HPV oncoprotein. In this study, we investigated whether polymorphisms at XRCC1, one of the DNA repair loci, could modulate the risk of tobacco-related leukoplakia and cancer in HPV-infected individuals.
  
  
  METHODS
  Tissue DNA from 83 oral cancer, 91 leukoplakia and 100 healthy controls were screened for HPV 16/18 infection and polymorphisms at XRCC1 by PCR-RFLP to estimate the risk of diseases independently and jointly.
  
  
  RESULTS
  Human papillomavirus infection was significantly associated with increased risk of leukoplakia and cancer (OR = 2.8, 95% CI = 1.2-6.5 and OR = 5.5, 95% CI = 1.6-19, respectively). Independently, genotypes at three polymorphic sites on XRCC1 did not modulate the risk of diseases but pooled variant haplotypes increased the risk of leukoplakia in overall and HPV non-infected (OR = 1.8, 95% CI = 1.2-2.8; OR = 2.2, 95% CI = 1.2-4.0, respectively) samples but not that of cancer.
  
  
  CONCLUSIONS
  The association between variant haplotypes at XRCC1 and risk of leukoplakia is pronounced in non-infected individuals since HPV oncoprotein could inhibit directly the DNA repair activity of XRCC1. But more samples of leukoplakia and cancer are essential to validate these results.
authors.affiliation: Human Genetics Unit, Biological Sciences Division, Indian Statistical Institute, Kolkata, India.
authors.forename: Mousumi
authors.initials: M
authors.lastname: Majumder
authors.forename: Dipanjana
authors.initials: D
authors.lastname: Indra
authors.forename: Puspita Das
authors.initials: PD
authors.lastname: Roy
authors.forename: Sayantan
authors.initials: S
authors.lastname: Datta
authors.forename: Jay Gopal
authors.initials: JG
authors.lastname: Ray
authors.forename: Chinmay K
authors.initials: CK
authors.lastname: Panda
authors.forename: Bidyut
authors.initials: B
authors.lastname: Roy