title: Characterisation of microbial communities within aggressive prostate cancer tissues.
abstract: BACKGROUND
  An infectious aetiology for prostate cancer has been conjectured for decades but the evidence gained from questionnaire-based and sero-epidemiological studies is weak and inconsistent, and a causal association with any infectious agent is not established. We describe and evaluate the application of new technology to detect bacterial and viral agents in high-grade prostate cancer tissues. The potential of targeted 16S rRNA gene sequencing and total RNA sequencing was evaluated in terms of its utility to characterise microbial communities within high-grade prostate tumours.
  
  
  METHODS
  Two different Massively Parallel Sequencing (MPS) approaches were applied. First, to capture and enrich for possible bacterial species, targeted-MPS of the V2-V3 hypervariable regions of the 16S rRNA gene was performed on DNA extracted from 20 snap-frozen prostate tissue cores from ten "aggressive" prostate cancer cases. Second, total RNA extracted from the same prostate tissue samples was also sequenced to capture the sequence profile of both bacterial and viral transcripts present.
  
  
  RESULTS
  Overall, 16S rRNA sequencing identifiedEnterobacteriaceaespecies common to all samples andP. acnesin 95% of analyzed samples. Total RNA sequencing detected endogenous retroviruses providing proof of concept but there was no evidence of bacterial or viral transcripts suggesting active infection, although it does not rule out a previous 'hit and run' scenario.
  
  
  CONCLUSIONS
  As these new investigative methods and protocols become more refined, MPS approaches may be found to have significant utility in identifying potential pathogens involved in disease aetiology. Further studies, specifically designed to detect associations between the disease phenotype and aetiological agents, are required.
authors.affiliation: Genetic Epidemiology Laboratory, Department of Pathology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, VIC, Australia 3010.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Yow
authors.affiliation: Department of Microbiology and Infectious Diseases, Royal Women's Hospital, Parkville, VIC Australia 3052 ; Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, VIC Australia 3010 ; Murdoch Childrens Research Institute, Parkville, VIC Australia 3052.
authors.forename: Sepehr N
authors.initials: SN
authors.lastname: Tabrizi
authors.affiliation: Human Genetics Foundation (HuGeF), Via Nizza, 52-10126 Torino, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Severi
authors.affiliation: Department of Surgery, University of Melbourne, Austin Health, 145 Studley Road, Heidelberg, VIC Australia 3084.
authors.forename: Damien M
authors.initials: DM
authors.lastname: Bolton
authors.affiliation: TissuPath, 92-96 Ricketts Road, Mount Waverley, VIC Australia 3149.
authors.forename: John
authors.initials: J
authors.lastname: Pedersen
authors.affiliation: Cancer Epidemiology and Intelligence Division, Cancer Epidemiology Centre, Cancer Council Victoria, Level 2, 615 St Kilda Road, Melbourne, VIC Australia 3004 ; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Level 3, 207 Bouverie Street, Carlton, VIC Australia 3053.
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.affiliation: Genetic Epidemiology Laboratory, Department of Pathology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, VIC, Australia 3010.
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Southey
keywords: 16S rRNA; Infection; Propionibacterium acnes; Prostate cancer; RNA; Sexually transmitted infection; cDNA