In Situ Proteomic Analysis of Histological Sections

To fully integrate molecular analysis with histology, it is essential to further develop and evaluate in situ tissue section-based technologies that are sensitive, quantitative, and high-throughput. In the proteomics field, immunohistochemistry (IHC) is the method of choice for in situ measurement of protein levels in histological sections. However, matrix- assisted laser desorption ionization-imaging mass spectrometry (MALDI-IMS) and related methods are emerging as additional multiplex in situ protein analysis tools. In this review, we discuss the application of these techniques in biomedical research and describe three newly developed technologies: multiplex tissue immunoblotting, indirect layered peptide array, and layered electrophoretic transfer (LET). In particular, we emphasize the LET technology as a novel in situ separation tool that allows for a more comprehensive proteomic analysis of a tissue sample while maintaining the important two-dimensional histological architecture.