Simultaneous detection of 10 cancer-associated amino acids and polyamines by high-performance liquid chromatography-high resolution mass spectrometry in pleural effusion cells obtained from lung adenocarcinoma patients

The deregulation of amino acid and polyamine metabolism is a hallmark of malignancy that regulates cancer cell proliferation, angiogenesis, and invasion. A sensitive mass spectrometry method was developed to simultaneously quantify 10 cancer-associated metabolites in pleural effusion cells for the diagnosis of malignancy and to complement conventional pleural cytology. Analytes were detected by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) using C8-reversed-phase HPLC for separation and sequential window acquisition of all theoretical fragment ion spectra (SWATH) acquisition for obtaining high-resolution quantitative MS/MS chromatograms. This method was validated and applied to pleural effusion cells from patients with lung adenocarcinoma (LUAD, n = 48) and those from benign controls (n = 23). The range of the above metabolites was 2 to 200ng/mL for proline, aspartate, ornithine, creatine, glutamine, glutamate, arginine, citrulline, and spermine and 10 to 1000ng/mL for putrescine. The intra-assay and inter-assay coefficient of variation was below 13.70% for all analytes. The joint detection of these metabolites in pleural effusion cells achieved a clinical sensitivity of 75.0% and specificity of 95.7% differentiating LUAD patients from benign controls. This assay enabled the detection of 10 cancer-associated metabolites in pleural effusion cells, and the increased concentration of these metabolites was correlated with the presence of LUAD.