Abstract 2876: Spatial immune cell atlas predicts the sensitivity to neoadjuvant PD-1 blockade treatment combined with radiotherapy in resectable esophageal squamous cell carcinoma

Abstract

Abstract Combination of radiotherapy and immunotherapy in neoadjuvant treatment seems a promising approach in resectable esophageal squamous cell squamous (ESCC). The clinical study of radiotherapy combined with PD-1 blockade therapy for neoadjuvant treatment of resectable ESCC shows good result. In order to investigate the underlying mechanism of the effectiveness of radiotherapy combined with immunotherapy in ESCC, we collected the pre and post neoadjuvant therapy samples from 5 responders and 5 non-responders ESCC patients and performed multiplexed tissue imaging using 28 markers. Using the detection measurements exported from QuPath, we performed the unsupervised clustering with Seurat and defined 20 cell types. Scimap was used to calculate the distance between different cell types. We found that CD4+ T, CD8+ T, cytotoxic CD8+ T cells and M1 macrophages showed an increase after treatment in both responders and non-responders. Tregs were decreased after neoadjuvant treatment in responder while there was no significant decrease in non-responder. And the distance between Tregs and cancer cells were increased in responders. Collectively, we provide an approach for investigating the underlying mechanism of the sensitivity to neoadjuvant PD-1 blockade treatment combined with radiotherapy in resectable ESCC using spatial multiplexed imaging. Citation Format: Xiaoyang Yin, Kailun Xu, Shu Zheng, Baosheng Li. Spatial immune cell atlas predicts the sensitivity to neoadjuvant PD-1 blockade treatment combined with radiotherapy in resectable esophageal squamous cell carcinoma [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(6_Suppl):Abstract nr 2876.