bacterial correlation and connection, "marker"?

I came across this potential bacterial "marker" with other biological aspects, so I'm noting the papers.

B193 Propionibacterium acnes infection of the prostate gland as a risk-factor and biomarker of prostate cancer. 

Andrew McDowell Centre for Stratified Medicine, School of Biomedical Sciences, Ulster University, Londonderry, United Kingdom.  

Abstract
Prostate cancer (PCa) is the most common male cancer in the UK, killing approximately 11,000 men every year. There is now increasing interest in the role played by the anaerobic bacterium Propionibacterium acnes in the aetiology of this condition via chronic, intracellular and asymptomatic infection of the prostate gland leading to oncogenesis. To investigate this, we developed a novel quantitative real-time PCR assay for retrospective detection of P. acnes in formalin-fixed paraffin-embedded tissue sections prepared from archived prostate biopsy samples. A total of 81 biopsy samples were examined from 53 patients with prostate carcinoma, versus 111 samples from 60 patients whose biopsies were histologically normal. Our assay revealed that 35% of men with PCa were positive for the presence of P. acnes in either one or both prostate lobes compared to only 8% of the normal tissue (Fisher’s exact test, 2-sided; p<0.001). This rate of detection is in keeping with previous culture-based studies, and equates to a 2-fold relative risk (95% CI: 1.45-2.75; p<0.0001) after adjustment for age; this level of risk approximates to having one first-degree relative diagnosed with the condition. No statistical association between the presence or absence of infection/ colonization and age, blood prostate specific antigen (PSA) levels or Gleason score was observed. Our studies suggest P. acnes infection of the prostate gland may be a potential risk factor for PCa development. Furthermore, the presence of P. acnes in cancerous tissue is also a highly specific biomarker for the condition versus PSA measurement (92% versus 65%).

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Propionibacterium acnes induces dysregulation of protease-activated receptor (PAR) gene activity in chronically infected prostate epithelial cells. Andrew McDowell et al, Centre for Stratified Medicine, School of Biomedical Sciences, Ulster University, Londonderry, United Kingdom. 

Abstract
There is now increasing interest in the role played by the anaerobic bacterium Propionibacterium acnes in the aetiology of prostate cancer (PCa) via chronic, intracellular and asymptomatic infection of the prostate gland leading to oncogenesis. To date, our understanding of how this bacterium could cause PCa remains unclear, although in vitro studies do demonstrate its ability to widely stimulate gene dysregulation and induce cellular transformation of prostate epithelial cells. We have taken a pathway-focused approach to understanding how this bacterium may effect RWPE-1 prostate epithelial cells via dysregulation of protease-activator gene activity (PAR), and associated downstream effectors and target genes. PARs are G-coupled cell surface proteins and are overexpressed in many different cancer types, including PCa where they are associated with tumour growth, invasion, metastasis and biochemical recurrence. Using a PAR signalling gene expression array, our results show that after a chronic 2-week infection in vitro with P. acnes, both PAR-1 and PAR-2 are significantly overexpressed, alongside significant dysregulation of genes encoding potential cancer mediators associated with inflammation, proliferation, angiogenesis and migration. Functional PAR-1 and PAR-2 upregulation was confirmed using a calcium mobilisation assay, which measures an ephemeral rise in intracellular calcium when cells are treated with agonist peptides against the receptors. These results provide additional evidence that P. acnes in the prostate gland may be a clinically relevant observation and a potential risk factor for PCa development.