Abstract

Introduction Macrophages, as a major immune cell population within the tumor microenvironment (TME), play a pivotal role in disease progression and therapeutic outcomes. This study aimed to identify key macrophage subsets associated with ESCC immunotherapy response. Methods Macrophage-specific marker gene associated with immunotherapy response was identified through single-cell RNA sequencing (scRNA-seq) analysis. The clinical relevance of CXCL2 + macrophages in ESCC patients was assessed by immunofluorescence staining. RNA sequencing was utilized to explore the role of CXCL2 in modulating macrophage functional phenotypes. The impact of CXCL2 on ESCC immunotherapy was validated by ESCC mouse model. Results ScRNA-seq analysis showed that CXCL2 was predominantly expressed in macrophages within TME and significantly upregulated in immunotherapy-responsive ESCC patients. Low infiltration of intratumoral CXCL2 + macrophages was correlated with poor survival. Mechanistically, CXCL2 promoted the phenotypic transition of macrophages to an immune-activated state by facilitating cytosolic Ca2+ influx. Additionally, CXCL2 suppressed tumor growth and enhanced the efficacy of anti-PD-1 antibody therapy in ESCC mouse models. Conclusion Macrophage-specific CXCL2 represents a novel biomarker for predicting immunotherapy efficacy and may potentiate the efficacy of anti-PD-1 therapy in ESCC patients.