# Tertiary Lymphoid Structures Are Associated with Favorable Clinical Outcomes and Negatively Correlated with Cancer-Associated Fibroblasts in Esophageal Cancer

## TL;DR

Tertiary lymphoid structures in esophageal cancer are linked to better outcomes and are negatively related to cancer-associated fibroblasts.

## Contribution

This study identifies TLSs as a prognostic factor and reveals their inverse relationship with CAFs in esophageal cancer.

## Key findings

- TLS presence correlates with improved overall and progression-free survival in esophageal cancer patients.
- TLSs are negatively correlated with cancer-associated fibroblasts in the tumor microenvironment.
- TLSs are associated with increased plasma cell infiltration and better nutritional status.

## Abstract

Tertiary lymphoid structures (TLSs) are immune cell aggregates that can develop within tumors. In esophageal cancer, we found that TLSs are present and associated with better patient outcomes. We also observed that cancer-associated fibroblasts (CAFs), which are important components of the tumor microenvironment, are related to TLS formation. These findings suggest that CAFs may influence the development of TLSs. Therapies targeting CAFs could therefore enhance TLS formation and potentially improve prognosis in patients with esophageal cancer.

Background: Esophageal cancer remains a highly aggressive malignant tumor with poor prognosis, despite advances in combination therapies and novel immunotherapies. Tertiary lymphoid structures (TLSs), characterized by densely packed CD20+ B cells in a germinal-center-like structure, have recently been recognized as immune-stimulating components within the tumor microenvironment. In contrast, cancer-associated fibroblasts (CAFs) are stromal cells expressing fibroblast-activating protein (FAP) involved in immunosuppression. Methods: In this retrospective study, 124 clinical samples from patients who underwent radical surgery for esophageal cancer at our institute were analyzed. We investigated whether TLSs could serve as a prognostic factor and examined their association with tumor microenvironment factors. Results: The presence of TLSs was an independent prognostic factor for overall and progression-free survival in multivariate analyses. A high level of TLS formation correlated with better nutritional status, fewer M2 macrophages, and greater plasma cell infiltration. Additionally, little TLS formation was observed in areas with abundant CAFs, and quantitative analyses revealed a significant negative correlation between TLSs and CAFs. Conclusions: TLSs enhance antitumor immunity via macrophages and plasma cells and can be a valuable prognostic indicator in patients undergoing surgery for esophageal cancer. Targeting CAFs may prove to be a promising therapeutic strategy to enhance tumor-immunity-related TLSs.