Fig. 1.

Schematic representation of the matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF-IMS) procedure. MALDI-IMS has developed as a promising tool for investigating the spatial distribution of biomolecules in intact tissue specimens. Ion densities of various molecules can be displayed as heat maps while preserving anatomical structures. For example, in gastric cancer, specially mounted tissues are subjected to matrix application and MALDI-TOF analysis. The discovered proteomes can be visualized in paraffin-embedded slides or visualized through confocal microscopy with a fluorescence-tagged biomarker antibody. MALDI-TOF molecular imaging can yield molecular images through an imaging software. IHC, immunohistochemistry.