title: Higher prevalence and gene amplification of HPV16 in oropharynx as compared to oral cavity.
abstract: OBJECTIVE
  The objective of this study was to clarify differences regarding HPV16 infection and gene amplification between the oral cavity and oropharynx in healthy individuals.
  
  
  METHODS
  The subjects were 94 healthy asymptomatic individuals (41 males, 53 females; mean age 58.6 years, range 16-97 years) who visited the Department of Oral and Maxillofacial Reconstructive Surgery of the Hiroshima University Hospital from 2014 to 2015. Oral epithelial cells were collected from oral rinse and pharynx gargle samples and placed in saline. The human endogenous retrovirus gene ERV3-1 was used as a reference to estimate the number of human cells in each sample. DNA samples were extracted from approximately 10,000 human cells and tested for HPV16 DNA by PCR using a type-specific primer. Similarly, we analyzed the HPV16 viral copy number in HPV16-positive cases using real-time PCR to examine genomic amplification.
  
  
  RESULTS
  The percentage of HPV16-positive cases was higher in the gargle (28.7%) as compared to the rinse (16.0%) samples. In the oral rinse samples, males (26.8%) showed a significantly higher rate of HPV16 than females (7.5%) (P=0.021). Importantly, in older subjects (aged 60-89 years), gargle samples showed a significantly higher rate of HPV16 (33.3%) than oral rinse samples (13.7%) (P=0.034). The average number of viral copies was approximately 8 times higher in the gargle than in the oral rinse samples (0.16±0.27 vs. 1.35±1.26 copy numbers per cell), a significant difference (P<0.001).
  
  
  CONCLUSIONS
  Our findings suggest that the oropharynx is more susceptible to HPV16 infection as compared to the oral cavity, while HPV16 gene amplification is also more commonly found in the oropharynx.
authors.affiliation: - Hiroshima University, Institute of Biomedical and Health Sciences, Department of Oral and Maxillofacial Surgery, Hiroshima, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Shigeishi
authors.affiliation: - Hiroshima University, Institute of Biomedical and Health Sciences, Department of Public Oral Health, Hiroshima, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugiyama
authors.affiliation: - Hiroshima University, Institute of Biomedical and Health Sciences, Department of Oral and Maxillofacial Surgery, Hiroshima, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Ohta
authors.affiliation: - Hiroshima University, Institute of Biomedical and Health Sciences, Department of Oral and Maxillofacial Surgery, Hiroshima, Japan.
authors.forename: Mohammad Zeshaan
authors.initials: MZ
authors.lastname: Rahman
authors.affiliation: - Hiroshima University, Institute of Biomedical and Health Sciences, Department of Oral and Maxillofacial Surgery, Hiroshima, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takechi
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002452:Cell Count; D056915:DNA Copy Number Variations; D004279:DNA, Viral; D005260:Female; D005784:Gene Amplification / Q000502:physiology*; D052162:Human papillomavirus 16 / Q000235:genetics*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000821:virology*; D009960:Oropharynx / Q000821:virology*; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology*; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D004279:DNA, Viral