Metabonomics by proton nuclear magnetic resonance in human pleural effusions: A route to discriminate between benign and malignant pleural effusions and to target small molecules as potential cancer biomarkers: 1 H-NMR Metabonomics in Pleural Effusions

BACKGROUND: Cytopathology is a noninvasive and cost-effective method for detecting cancer cells in pleural effusions (PEs), although in many cases, the diagnostic performance is hindered by the paucity of significant cells or the lack of clear morphological criteria. This study presents the results of an omics approach to improving the diagnostic performance of PE cytology. METHODS: Metabolic profiling with proton nuclear magnetic resonance (1 H-NMR) was performed for 92 PEs (44 malignant cases of 8 different cancers and 48 benign cases of 7 nonneoplastic conditions). Light's criteria were used to further classify PEs as transudates or exudates, and 1 H-NMR spectroscopy was used to differentiate malignant pleural effusions (mPEs) from benign pleural effusions (bPEs). RESULTS: 1 H-NMR metabolic analysis showed clearly different spectra for mPEs and bPEs in the regions of the signals due to lipids, branched amino acids, and lactate, which were increased in mPEs. Transudates and exudates in bPEs were differentiated as well on the basis of the 1 H-NMR signals from lipids and lipoproteins, which were increased in exudates. CONCLUSIONS: Subject to validation in further larger studies, 1 H-NMR metabonomics could be an effective and reliable ancillary tool for PE investigations and diagnoses.