Frequency and typing of Propionibacterium acnes in prostate tissue obtained from men with and without prostate cancer.
BACKGROUND
Prostate cancer is the most common cancer among men in Western countries but the exact pathogenic mechanism of the disease is still largely unknown. An infectious etiology and infection-induced inflammation has been suggested to play a role in prostate carcinogenesis and Propionibacterium acnes has been reported as the most prevalent microorganism in prostatic tissue. We investigated the frequency and types of P. acnes isolated from prostate tissue samples from men with prostate cancer and from control patients without the disease.


METHODS
We included 100 cases and 50 controls in this study. Cases were men diagnosed with prostate cancer undergoing radical prostatectomy and controls were men undergoing surgery for bladder cancer without any histological findings of prostate cancer. Six biopsies taken from each patient's prostate gland at the time of surgery were used for cultivation and further characterization of P. acnes.


RESULTS
The results revealed that P. acnes was more common in men with prostate carcinoma than in controls, with the bacteria cultured in 60 % of the cases vs. 26 % of the controls (p = 0.001). In multivariable analyses, men with P. acnes had a 4-fold increase in odds of a prostate cancer diagnosis after adjustment for age, calendar year of surgery and smoking status (OR: 4.46; 95 % CI: 1.93-11.26). To further support the biologic plausibility for a P. acnes infection as a contributing factor in prostate cancer development, we subsequently conducted cell-based experiments. P. acnes- isolates were co-cultured with the prostate cell line PNT1A. An increased cell proliferation and cytokine/chemokine secretion in infected cells was observed.


CONCLUSIONS
The present study provides further evidence for a role of P. acnes in prostate cancer development.
Department of Urology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden ; A Member of the Transdisciplinary Prostate Cancer Partnership (TopCaP), Örebro, Sweden ; Department of Urology, Örebro University Hospital, SE-701 85 Örebro, Sweden.
Sabina
S
Davidsson
Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Paula
P
Mölling
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA USA ; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA USA ; A Member of the Transdisciplinary Prostate Cancer Partnership (TopCaP), Örebro, Sweden.
Jennifer R
JR
Rider
Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Magnus
M
Unemo
Department of Laboratory Medicine, Pathology, Örebro University Hospital, Örebro, Sweden ; Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Mats G
MG
Karlsson
Department of Urology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden ; A Member of the Transdisciplinary Prostate Cancer Partnership (TopCaP), Örebro, Sweden.
Jessica
J
Carlsson
Department of Urology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden ; A Member of the Transdisciplinary Prostate Cancer Partnership (TopCaP), Örebro, Sweden.
Swen-Olof
SO
Andersson
Department of Clinical Microbiology, Umeå University, Umeå, Sweden.
Fredrik
F
Elgh
Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Bo
B
Söderquis
Department of Urology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden ; A Member of the Transdisciplinary Prostate Cancer Partnership (TopCaP), Örebro, Sweden.
Ove
O
Andrén
Infection; Inflammation; Propionibacterium acnes; Prostate cancer