title: Coexistence of episomal and integrated HPV16 DNA in squamous cell carcinoma of the cervix.
abstract: OBJECTIVE
  To investigate the integration of human papillomavirus (HPV)16 in 13 HPV16 positive cervical squamous carcinomas.
  
  
  METHODS
  Samples were investigated by Southern blot analysis of the Pst I digestion pattern, two-dimensional gel-electrophoresis, and in situ hybridisation.
  
  
  RESULTS
  Integration of HPV16 was found in all cases. In 12 biopsy specimens episomal HPV16 DNA and integrated HPV16 DNA were seen. The episomal DNA occurred as dimers and multimers. In situ hybridisation showed that both integrated and episomal HPV16 DNA were present in the same cell in most tumour cell nuclei.
  
  
  CONCLUSIONS
  An intact episomal E2 gene is present in most cases of these cervical cancers, and could therefore replace the regulatory function of an integrated defective E2 gene.
authors.affiliation: Biotechnology Center of Oslo, University of Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Kristiansen
authors.forename: A
authors.initials: A
authors.lastname: Jenkins
authors.forename: R
authors.initials: R
authors.lastname: Holm
mesh_terms: D015139:Blotting, Southern; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000382:microbiology; D004279:DNA, Viral / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D027383:Papillomaviridae / Q000235:genetics*; D015183:Restriction Mapping; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000382:microbiology; D016662:Virus Integration / Q000235:genetics*
chemical_list: D004279:DNA, Viral