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Title: Volatile organic compounds: novel potential biomarkers in bladder cancer diagnosis
Author: Johnson , Emmanuel Uche
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2013
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Bladder cancer is an important global disease. The gold standard for diagnosis is cystoscopy and biopsy; both are invasive and require highly trained personnel. In a majority of cases, treated patients are followed up by frequent cystoscopies lasting several years. The discovery of biomarkers indicating which individuals should proceed to cystoscopy would be an important addition to bladder cancer management. The odour of urine is produced by volatile organic compounds, (VOCs), detectable by gas chromatography and mass spectrometry (GC-MS). An analysis of the VOCs in urine from various groups of individuals including patients with bladder cancer is undertaken in search of possible discriminating compounds, which could be harnessed in future as a potential screening tool or adjunct in bladder cancer management. Methods First void urine was obtained from 64 patients with new non-muscle invasive bladder cancer, 71 cancer free patients with haematuria and 51 asymptomatic volunteers. After equilibration, the headspace above these pH adjusted urine samples was extracted for 20minutes, using a carboxen / polydimethylsiloxane solid phase micro-extraction fibre (SPME). This was followed by desorption and VOC identification by GC-MS. Results Urine headspace VOCs under acidic conditions, (pH of modified urine 2), were found to be discriminating. Identified compounds were analyzed using forward stepwise discriminant analysis: 9 VOCs when used together, gave 84.7% correct classification of samples (Haematuria control v Bladder cancer) with no change on cross validation of results. The calculated sensitivity and specificity of this model is 76.6% and 92.9% respectively, with Positive predictive value of 90.7% and Negative predictive value of 92.9%. These results are comparable, and in some cases better than those obtained using commercially available urinary bladder cancer biomarkers. Conclusion Volatile organic compounds in urinary head space change with the development of bladder cancer. Urinary VOCs are exciting novel potential biomarkers in the detection of bladder cancer.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available