title: IL-1RN VNTR polymorphism as a susceptibility marker for nasopharyngeal carcinoma in Portugal.
abstract: BACKGROUND
  Nasopharyngeal carcinoma (NPC) is a rare malignancy in Western countries that is widely associated with the infection by Epstein-Barr virus (EBV). Several studies have showed that a common allele (allele 2) of the 86-bp variable number of tandem repeats (VNTR) polymorphism within intron 2 of the interleukin 1 receptor antagonist (IL-1RN) gene is associated with several disorders, including viral-associated cancers.
  
  
  METHODS
  We have developed a hospital-based case-control study to characterise the role of the IL-1RN 86-bp VNTR polymorphism in the development of NPC with 112 patients with the disease and 433 healthy individuals from the northern region of Portugal. IL-1RN genotypes were combined according to the number of repeats: allele 2 (A2), the short allele that corresponds to two repeats, and L, the long allele that corresponds to three or more repeats.
  
  
  RESULTS
  Our study revealed that 31.2% of NPC patients were IL-1RN A2*A2, compared with 9.7% observed in the control group. The statistical analysis revealed that IL-1RN*A2 homozygosity for the A2 allele was associated with a fourfold increased risk for NPC development (p<0.001). Additionally, cumulative hazard analysis revealed that estimated median age of onset of NPC is significantly (p<0.001) different for A2*A2 homozygous versus non-A2*A2 (57.0 vs. 74.0, respectively).
  
  
  CONCLUSIONS
  This is the first study to evaluate the role of the IL-1RN VNTR in NPC development in Portugal. Our study indicates IL-1RN*A2 homozygosity as a significant risk marker in our population and that it should be further investigated for the potential role in the definition of a susceptibility profile for NPC onset.
authors.affiliation: Molecular Oncology Group, Portuguese Institute of Oncology of Porto, Porto, Portugal. hugomls@gmail.com
authors.forename: Hugo
authors.initials: H
authors.lastname: Sousa
authors.forename: Eduardo
authors.initials: E
authors.lastname: Breda
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Santos
authors.forename: Raquel
authors.initials: R
authors.lastname: Catarino
authors.forename: Daniela
authors.initials: D
authors.lastname: Pinto
authors.forename: Paulo
authors.initials: P
authors.lastname: Canedo
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Machado
authors.forename: Rui
authors.initials: R
authors.lastname: Medeiros
mesh_terms: D000328:Adult; D017668:Age of Onset; D000483:Alleles; D020029:Base Pairing / Q000235:genetics; D002277:Carcinoma / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006720:Homozygote; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics*; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011174:Portugal; D012307:Risk Factors
chemical_list: D005819:Genetic Markers; D053590:Interleukin 1 Receptor Antagonist Protein