title: GC-MS metabolomics-based approach for the identification of a potential VOC-biomarker panel in the urine of renal cell carcinoma patients.
abstract: The analysis of volatile organic compounds (VOCs) emanating from biological samples appears as one of the most promising approaches in metabolomics for the study of diseases, namely cancer. In fact, it offers advantages, such as non-invasiveness and robustness for high-throughput applications. The purpose of this work was to study the urinary volatile metabolic profile of patients with renal cell carcinoma (RCC) (n = 30) and controls (n = 37) with the aim of identifying a potential specific urinary volatile pattern as a non-invasive strategy to detect RCC. Moreover, the effect of some confounding factors such as age, gender, smoking habits and body mass index was evaluated as well as the ability of urinary VOCs to discriminate RCC subtypes and stages. A headspace solid-phase microextraction/gas chromatography-mass spectrometry-based method was performed, followed by multivariate data analysis. A variable selection method was applied to reduce the impact of potential redundant and noisy chromatographic variables, and all models were validated by Monte Carlo cross-validation and permutation tests. Regarding the effect of RCC on the urine VOCs composition, a panel of 21 VOCs descriptive of RCC was defined, capable of discriminating RCC patients from controls in principal component analysis. Discriminant VOCs were further individually validated in two independent samples sets (nine RCC patients and 12 controls, seven RCC patients with diabetes mellitus type 2) by univariate statistical analysis. Two VOCs were found consistently and significantly altered between RCC and controls (2-oxopropanal and, according to identification using NIST14, 2,5,8-trimethyl-1,2,3,4-tetrahydronaphthalene-1-ol), strongly suggesting enhanced potential as RCC biomarkers. Gender, smoking habits and body mass index showed negligible and age-only minimal effects on the urinary VOCs, compared to the deviations resultant from the disease. Moreover, in this cohort, the urinary volatilome did not show ability to discriminate RCC stages and histological subtypes. The results validated the value of urinary volatilome for the detection of RCC and advanced with the identification of potential RCC urinary biomarkers.
authors.affiliation: UCIBIO@REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Márcia
authors.initials: M
authors.lastname: Monteiro
authors.affiliation: UCIBIO@REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Moreira
authors.affiliation: UCIBIO@REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Pinto
authors.affiliation: Cancer Biology & Epigenetics Group, Portuguese Oncology Institute of Porto (IPOPorto), Porto, Portugal.|Department of Pathology, Portuguese Oncology Institute of Porto (IPOPorto), Porto, Portugal.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Pires-Luís
authors.affiliation: Cancer Biology & Epigenetics Group, Portuguese Oncology Institute of Porto (IPOPorto), Porto, Portugal.|Department of Pathology, Portuguese Oncology Institute of Porto (IPOPorto), Porto, Portugal.|Department of Pathology and Molecular Immunology-Biomedical Sciences Institute (ICBAS), University of Porto, Porto, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Henrique
authors.affiliation: Cancer Biology & Epigenetics Group, Portuguese Oncology Institute of Porto (IPOPorto), Porto, Portugal.|Department of Pathology and Molecular Immunology-Biomedical Sciences Institute (ICBAS), University of Porto, Porto, Portugal.
authors.forename: Carmen
authors.initials: C
authors.lastname: Jerónimo
authors.affiliation: UCIBIO@REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Maria de Lourdes
authors.initials: ML
authors.lastname: Bastos
authors.affiliation: CICECO-Instituto de Materiais de Aveiro (CICECO/UA), Departamento de Química, Universidade de Aveiro, Aveiro, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gil
authors.affiliation: UCIBIO@REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal.|UFP Energy, Environment and Health Research Unit (FP-ENAS), Universidade Fernando Pessoa, Porto, Portugal.
authors.forename: Márcia
authors.initials: M
authors.lastname: Carvalho
authors.affiliation: UCIBIO@REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Guedes de Pinho
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000652:urine*; D002292:Carcinoma, Renal Cell / Q000652:urine*; D016022:Case-Control Studies; D016002:Discriminant Analysis; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007680:Kidney Neoplasms / Q000652:urine*; D016018:Least-Squares Analysis; D008297:Male; D055432:Metabolomics; D008875:Middle Aged; D025341:Principal Component Analysis; D055549:Volatile Organic Compounds / Q000652:urine*
chemical_list: D014408:Biomarkers, Tumor; D055549:Volatile Organic Compounds
keywords: biomarkers; gas chromatography-mass spectrometry; multivariate statistical analysis; renal cell carcinoma; urine; volatile organic compounds