title: Effect of smoking on the genetic makeup of toll-like receptors 2 and 6.
abstract: BACKGROUND
  Cigarette smoking is a major risk factor for lung cancer, asthma, and oral cancer, and is central to the altered innate immune responsiveness to infection. Many hypotheses have provided evidence that cigarette smoking induces more genetic changes in genes involved in the development of many cigarette-related diseases. This alteration may be from single-nucleotide polymorphisms (SNPs) in innate immunity genes, especially the toll-like receptors (TLRs).
  
  
  OBJECTIVE
  In this study, the genotype frequencies of TLR2 and TLR6 in smoking and nonsmoking population were examined.
  
  
  METHODS
  Saliva samples were collected from 177 smokers and 126 nonsmokers. The SNPs used were rs3804100 (1350 T/C, Ser450Ser) and rs3804099 (597 T/C, Asn199Asn) for TLR2 and rs3796508 (979 G/A, Val327Met) and rs5743810 (745 T/C, Ser249Pro) for TLR6.
  
  
  RESULTS
  Results showed that TLR2 rs3804100 has a significant effect in short-term smokers (OR =2.63;P=0.04), and this effect is not observed in long-term smokers (>5 years of smoking). Therefore, this early mutation may be repaired by the DNA repair system. For TLR2 rs3804099, the variation in genotype frequencies between the smokers and control patients was due to a late mutation, and its protective role appears only in long-term smokers (OR =0.40,P=0.018). In TLR6 rs5743810, the TT genotype is significantly higher in smokers than in nonsmokers (OR =6.90). The effect of this SNP is observed in long-term smokers, regardless of the smoking regime per day.
  
  
  CONCLUSIONS
  TLR2 (rs3804100 and rs3804099) and TLR6 (rs5743810) can be used as a potential index in the diagnosis and prevention of more diseases caused by smoking.
authors.affiliation: Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Kohailan
authors.affiliation: Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Alanazi
authors.affiliation: Département de Stomatologie, Faculté de Médecine Dentaire, Groupe de Recherche en Écologie Buccale, Université Laval, Québec City, QC, Canada.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Rouabhia
authors.affiliation: Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Alamri
authors.affiliation: Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Narasimha Reddy
authors.initials: NR
authors.lastname: Parine
authors.affiliation: Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Alhadheq
authors.affiliation: Dental Biomaterial Research Chair, Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Santhosh
authors.initials: S
authors.lastname: Basavarajappa
authors.affiliation: Dental Biomaterial Research Chair, Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Abdul Aziz
authors.initials: AA
authors.lastname: Abdullah Al-Kheraif
authors.affiliation: Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Abdelhabib
authors.initials: A
authors.lastname: Semlali
keywords: TLR2; TLR6; genotyping; polymorphism; smoking; toll-like receptor