Sequential Orbitrap Secondary Ion Mass Spectrometry and Liquid Extraction Surface Analysis-Tandem Mass Spectrometry-Based Metabolomics for Prediction of Brain Tumor Relapse from Sample-Limited Primary Tissue Archives

We present here a novel surface mass spectrometry strategy to perform untargeted metabolite profiling of formalin-fixed paraffin-embedded pediatric ependymoma archives. Sequential Orbitrap secondary ion (3D OrbiSIMS) and liquid extraction analysis-tandem (LESA-MS/MS) permitted the detection 887 metabolites (163 chemical classes) from tumor tissue microarrays (diameter: <1 mm; thickness: 4 ?m). From these 163 classes, 60 classes were detected with both techniques, whilst LESA-MS/MS 3D OrbiSIMS individually allowed another 83 20 unique respectively. Through data fusion multivariate analysis, we able identify key corresponding pathways predictive relapse, which retrospectively confirmed by gene expression analysis publicly available data. Altogether, this sequential has shown be versatile tool high-throughput on sample-limited