Abstract 6879: Development of a rapid multiplex immunohistochemistry for characterizing tumor-immune microenvironment

Abstract Intratumoral immune profiles have been related to prognosis and therapeutic efficacy; this could result in personalized treatment based on biomarkers. Although techniques for multifactorial evaluation of different tumor-immune microenvironments have been established, their practical implementation in clinical settings still requires further improvement, where the time required for testing needs to be reduced and the technology needs to be clinically validated. To develop a multiplex, quantitative, and rapid tissue evaluation method based on clinically established standard immunohistochemistry (IHC), we attempted to develop 6-marker rapid multiplex IHC based on our previously reported 14-marker multiplex IHC via the reduction of the number of labels and speeding up the staining procedure (Tsujikawa et al. Cell Reports, 2017). First, we confirmed whether immunological features that were found to be associated with prognosis in 14-marker multiplex IHC analyses could be identified with fewer labels. Quantitative results by selected six markers exhibited significant correlation with those by 14 markers in terms of immune classifications based on the balance of lymphoid and myeloid cells. Next, we developed a rapid staining protocol by optimizing the reaction temperature, chromogen, and washing time, allowing the completion of 6-marker analysis in 5 hours and 49 minutes as opposed to several days required for the conventional multiplex IHC. By using six markers, validation in benign tonsil tissue and head and neck cancer tissue exhibited significant correlation between rapid and standard multiplex IHC in terms of staining intensities, densities of T cells, macrophages, lymphoid/myeloid immune cells ratios, and spatial profiles of intratumoral immune infiltrates. This method may enable a quantitative assessment of tumor-immune microenvironment on a clinically feasible time scale, which promote the development of tissue biomarker-guided therapeutic strategies. Citation Format: Alisa Kimura, Takahiro Tsujikawa, Hiroki Morimoto, Junichi Mitsuda, Sumiyo Saburi, Shigeyuki Mukudai, Hikaru Nagao, Nana Sakurai, Nanako Murakami, Aya Miyagawa-Hayashino, Hiroshi Ogi, Saya Shibata, Eiichi Konishi, Kyoko Itoh, Shigeru Hirano. Development of a rapid multiplex immunohistochemistry for characterizing tumor-immune microenvironment abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 6879.