Spatial analysis of the tumor microenvironment can be achieved via the novel SignalStarTM multiplex immunohistochemistry assay 3651

Abstract Description The relevance of the spatial context of the increasing number of potential biomarkers within the tumor microenvironment (TME) has resulted in a need for reliable and accurate multiplex immunohistochemical (mIHC) assays. The SignalStar mIHC assay from Cell Signaling Technology is a novel approach that was utilized to amplify and visualize up to 8 targets within the same formalin fixed, paraffin-embedded (FFPE) tissue section without the need for cycling of antibodies or fluorophore deposition. Here, we compare each target in an 8-plex panel consisting of T-cell exhaustion markers to the canonical chromogenic IHC assay. We also demonstrate the value of amplification when detecting lower abundance functional markers by comparing the percent positivity of SignalStar amplified targets to that achieved with direct and indirect immunofluorescence. Furthermore, we highlight the flexibility of this assay via the usage of a SignalStar secondary antibody, which allows for the incorporation of any IHC-validated rabbit antibody into a panel. Lastly, we also compare the SignalStar assay to other mIHC assays with respect to signal intensity and percent cell positivity. Ultimately, our data demonstrates that the SignalStar mIHC assay is a powerful tool that accurately characterizes the complex TME, allowing researchers to better understand immunotherapeutic approaches and other treatment strategies. Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)