Abstract 387: Analysis of FFPE human tumor tissues using CODEX with signal amplification

Abstract

Abstract Analysis of FFPE human tumor tissues using CODEX with signal amplification Characterizing the complexities of the tumor microenvironment is fundamental to understanding disease mechanisms. The spatial relationships between infiltrating immune cells and the remodeling of the cellular matrix is widely recognized as a key component to defining tumor heterogeneity. Current methodologies for studying cells within the context of tissue architecture, like traditional immunofluorescence (IF) and immunohistochemistry (IHC), are limiting–allowing the assessment of only a few parameters at a time. The CODEX technology has overcome this limitation through a DNA-based labeling strategy, involving adding and removing dye-labeled oligonucleotides (reporters) across multiple cycles to oligonucleotide-labeled antibodies. In this manner, tens of markers can be analyzed on the same tissue. Additionally, CODEX interfaces with existing inverted microscopes and provides a cost-effective, fully automated platform for highly multiplexed imaging. Recently, we expanded our workflow to amplify the fluorescent signal intensities of low expressing biomarkers by combining Tyramide Signal Amplification (TSA) with CODEX. This approach is associated with key markers used to analyze the tumor microenvironment, including PD-L1 and PD-1. We demonstrated signal amplification of more than 50X compared with non-amplified signal. Here, we present the analysis of CODEX data for a panel of over 20 biomarkers on human FFPE tissue including signal amplification of PD-L1, PD-1 and foxp3. Through amplification of key markers as the final cycle of a CODEX experiment, low expression can be measured and used to identify key cell types, including Treg cells and PD-L1 positive tumor and stromal regions. Citation Format: Sejal Mistry, Gajalakshmi Dakshinamoorthy, Jessica Yuan, Pieter Noordam, Joseph Kim, Won-Mean Lee, Julia Kennedy-Darling. Analysis of FFPE human tumor tissues using CODEX with signal amplification [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 387.