1P-15 PDF
リアルタイムメタボローム解析システムの構築とその臨床応用
Probe electrospray ionization (PESI) is an ambient ionization method and suitable for direct ionization of biological molecules from living animals. To use the PESI for real-time mass spectrometry (MS) system, we installed it in single quadrupole mass spectrometer (Shimadzu LCMS-2020) with some modifications. We termed it “non-proximate PESI-MS” for this system. Our previous study demonstrates that Non-proximate PESI-MS can directly detect the moleculer profile of liver tissue in anesthetized mouse, and trace the concentration of exogenous compound from liver surface.
Non-proximate PESI-MS can detect the low moleculer weight metabolites (< m/z 2000). The expression profiles of metabolites in tissues or blood give us important information in diagnosis of diseases. To validate the value of this system, we applied Non-proximate PESI-MS to real-time diagnosis of oral squamous cell carcinoma and brain tumor (glioma). First, we established programs for database construction and discriminant analysis, and collected the mass spectra from noncancerous/cancerous specimens. These data were fed into learning machine for making diagnosis. Subsequent cross validation trial gave as accuracy of over 85% in cancer diagnosis. These resuls strongly suggest that Non-proximate PESI-MS can discriminate the cancers based on profiles of metabolite without identification of each molecular species.