title: Solid phase microextraction, mass spectrometry and metabolomic approaches for detection of potential urinary cancer biomarkers--a powerful strategy for breast cancer diagnosis.
abstract: A sensitive assay to identify volatile organic metabolites (VOMs) as biomarkers that can accurately diagnose the onset of breast cancer using non-invasively collected clinical specimens is ideal for early detection. Therefore the aim of this study was to establish the urinary metabolomic profile of breast cancer patients and healthy individuals (control group) and to explore the VOMs as potential biomarkers in breast cancer diagnosis at early stage. Solid-phase microextraction (SPME) using CAR/PDMS sorbent combined with gas chromatography-mass spectrometry was applied to obtain metabolomic information patterns of 26 breast cancer patients and 21 healthy individuals (controls). A total of seventy-nine VOMs, belonging to distinct chemical classes, were detected and identified in control and breast cancer groups. Ketones and sulfur compounds were the chemical classes with highest contribution for both groups. Results showed that excretion values of 6 VOMs among the total of 79 detected were found to be statistically different (p<0.05). A significant increase in the peak area of (-)-4-carene, 3-heptanone, 1,2,4-trimethylbenzene, 2-methoxythiophene and phenol, in VOMs of cancer patients relatively to controls was observed. Statistically significant lower abundances of dimethyl disulfide were found in cancer patients. Bioanalytical data were submitted to multivariate statistics [principal component analysis (PCA)], in order to visualize clusters of cases and to detect the VOMs that are able to differentiate cancer patients from healthy individuals. Very good discrimination within breast cancer and control groups was achieved. Nevertheless, a deep study using a larger number of patients must be carried out to confirm the results.
authors.affiliation: CQM/UMa - Centro de Química da Madeira, Centro de Ciências Exactas e da Engenharia, Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal.
authors.forename: Catarina L
authors.initials: CL
authors.lastname: Silva
authors.forename: Mário
authors.initials: M
authors.lastname: Passos
authors.forename: José S
authors.initials: JS
authors.lastname: Câmara
mesh_terms: D000327:Adsorption; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000652:urine*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000652:urine; D016022:Case-Control Studies; D042241:Early Diagnosis; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D025341:Principal Component Analysis; D052617:Solid Phase Microextraction / Q000379:methods
chemical_list: D014408:Biomarkers, Tumor