CX3CR1⁺ CD8⁺ Cytotoxic T Cells Drive Tumor Killing in Esophageal Squamous Cell Carcinoma During Neoadjuvant Therapy

Here, we performed single-cell RNA sequencing (scRNA-seq), T cell receptor (TCR) sequencing, and whole exome sequencing (WES) on 52 ESCC patients from a phase III neoadjuvant clinical trial to characterize the tumor microenvironment (TME) and its association with therapeutic outcomes.

We identified a selective expansion of non-exhausted cytotoxic CD8⁺ T cells, particularly CX3CR1⁺ CD8⁺ T cells, in well responders, driven by the CX3CL1-CX3CR1 axis. These cells exhibited high cytotoxicity, clonal expansion, and tumor-killing potential, while exhausted T cell subsets, including CXCL13⁺ CD8⁺ T cells, were reduced in well responders. Pre-treatment tumor mutational profiles revealed that a high cancer cell fraction (CCF) mutation burden and neoantigen abundance were predictive of response, with immune editing reducing immunogenic mutations post-treatment.