Microbial community profiling by next-generation DNA sequencing of adenocarcinoma of the prostate with evidence of ochratoxin A producing fungi

Abstract

Background: Prostatic carcinomas are a leading cancer and leading cause of mortality in the developed world. The etiology is diverse with underlying patient genetics, environmental factors, and microbial associations. Sequencing DNA for microbes allows the detection of potential disease relationships.

Objective: Targeted 16S (prokaryotic) and 18S (eukaryotic) rDNA sequencing was performed to map the tumor microbial flora.

Design: Twelve patients undergoing elective laparoscopic prostatectomy for biopsy proven adenocarcinoma of the prostate were enrolled. PCR and amplicon based sequencing was conducted; a portion of the sequencing results were confirmed by special stains.

Setting: Patients were recruited by the urologist were prospectively scheduled for radical prostatectomy by 'Da Vinci' robotically assisted procedure in an outpatient setting. Samples were portioned in the hospital surgical suite at the time of prostatectomy.

Participants: Male patients were requested to enter the study on a first come basis.

Outcome measurement and statistical analysis: Average age of the 12 participants was 64.3 years.

Results and limitations: DNA reads were detected and by 'best match' were identified belonging to Perkinsus, Hydrurus, Diversispora and Funneliformis genera, few samples displayed bacteria. Out of the 12 total patients, 11 patients had detectable DNA sequences matching arbuscular mycorrhizal fungi in the Glomeromycetes Class; Funneliformis mosseae and Diversasporum versiformis. Specific PCR for arbuscular mycorrhizal fungi failed to confirm Glomeromycetes Class; in-depth taxonomic analysis suggests a newer fungal grouping, not falling within an accepted Phylum of fungi. Calcoflour white staining of histological sections confirmed potential fungal markers in all 12 cases. Ochratoxin A antigen was identified by immunofluorescence in all 12 patient samples. The study was limited by the low sample volume and disease free normal controls.

Conclusions: Fungi may play a significant role in adenocarcinoma of the prostate.

Keywords: Calcofluor; DNA sequencing; Microbial community analysis; Ochratoxin; Prostatic adenocarcinoma; fungi.