NanoString Technologies 1 article published in JoVE Cancer Research Spatial Profiling of Protein and RNA Expression in Tissue: An Approach to Fine-Tune Virtual Microdissection Veronica Ibarra-Lopez1, Sangeeta Jayakar1, Yeqing Angela Yang2, Ciara Martin3, Zora Modrusan2, Sandra Rost1 1Department of Pathology, Genentech, 2Department of Microchemistry, Proteomics, Lipidomics & Next Generation Sequencing (MPL-NGS), Genentech, 3NanoString Technologies Here, we describe a protocol for fine-tuning regions of interest (ROIs) for Spatial Omics technologies to better characterize the tumor microenvironment and identify specific cell populations. For proteomics assays, automated customized protocols can guide ROI selection, while transcriptomics assays can be fine-tuned utilizing ROIs as small as 50 µm.