Porphyrins are increased in the faeces of patients with prostate cancer: a case-control study

• Published in: BMC cancer Vol. 18; no. 1; pp. 1090 - 6
• Main Authors: Gotardelo, Daniel Riani, Courrol, Lilia Coronato, Bellini, Maria Helena, de Oliveira Silva, Flávia Rodrigues, Soares, Carlos Roberto Jorge
• Format: Journal Article
• Language: English
• Published: London BioMed Central 12.11.2018; BioMed Central Ltd; BMC
• Subjects: Acetone; Aged; Animal models; Antigens; Biological markers; Biomarker; Biomarkers; Biomarkers, Tumor; Biomedical and Life Sciences; Biomedicine; Biosynthesis; Brazil; Cancer Research; Case-Control Studies; Cell division; Composition; Development and progression; Enzymes; Faeces; Feces; Feces - chemistry; Fluorescence spectroscopy; Health aspects; Health Promotion and Disease Prevention; Heme - metabolism; Hemoglobin; Humans; Hypotheses; Male; Medical diagnosis; Medicine/Public Health; Metabolism; Metabolites; Middle Aged; Oncology; Porphyrin; Porphyrins; Porphyrins - metabolism; Prostate Cancer; Prostatic Neoplasms - genetics; Prostatic Neoplasms - metabolism; Protoporphyrin; Protoporphyrin IX; Research Article; Sensitivity and Specificity; Socioeconomic Factors; Spectrometry, Fluorescence; Spectrum analysis; Statistical analysis; Studies; Surgical Oncology; Translational oncology; Tumors; Brazil; Fluorescence spectroscopy; Biomarker; Prostate Cancer; Porphyrin; Faeces
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/s12885-018-5030-1

Background Experimental models of prostate cancer have demonstrated increased levels of protoporphyrin IX (PpIX) in the blood and faeces of mice. Hence, the quantification of these autofluorescent molecules could be hypothesized to be a potential marker for this type of tumour. In this case-control study, the autofluorescence of porphyrins in human faeces from patients with prostate cancer and control subjects was analysed using fluorescence spectroscopy. Methods First, 3 mL of analytical-grade acetone was added to 0.3 g of faeces, and the mixture was macerated and centrifuged at 4000 rpm for 15 min. The supernatant was analysed spectroscopically. The emission spectra from 550 to 750 nm were obtained by exciting the samples at 405 nm. Results A significant difference between the samples from control and cancer subjects was established in the spectral region of 670–675 nm ( p  = 0.000127), which corresponds to a significant increase in faecal porphyrins in patients with cancer. There was no statistically significant correlation between PSA levels and faecal porphyrins. Conclusion In this preliminary study conducted in humans, the results show a simple and non-invasive method to assess faecal porphyrins, which have the potential to function as a tumour biomarker in patients with prostate cancer. This approach has improved sensitivity and specificity over PSA testing. Additional prospective studies with larger sample sizes are required to validate these findings.