ABSTRACT – ANALYTICAL CORE The Analytical Core will serve as a central resource for the deep systems-level molecular characterization of biological samples generated by the Projects and from the Biospecimens Core. The primary objective of this Core is to integrate diverse single cell, bulk, and spatial analytical platforms to define the complex interactions between brain tumor cells and the associated brain tumor microenvironment (TME). To this end, we have developed an analytical platform encompassing transcriptional profiling at the single cell, single nuclei, and bulk tissue scale; protein expression profiling, phosphoproteomics and immunopeptidomics with cell type-specific resolution; and quantitative metabolomics and drug distribution profiling with high spatial resolution by mass spectrometry imaging (MSI). These complementary analytical approaches have the requisite sensitivity to generate ultra-deep systems-level molecular profiling of 10-20 micron thick tissues from single core biopsies; performance of our platform has already been demonstrated on multiple image-guided core biopsies from geographically distinct regions of a GBM tumor. Multi-omics data acquired in our Analytical Core will be managed using a FAIR compliant metadata management tool that prioritizes connections between samples and defines discrete sample types that can be freely connected as described in the Overall Section of our proposal. The Analytical Core will provide expert personnel, facilitate the sharing of knowledge within the program, and maintain the sophisticated equipment necessary to generate data for both Projects. By acting as a common resource, the Analytical Core provides expertise for each Project.