Objective To explore the effect of the expression level of CXC motif chemokine ligand 13 (CXCL13) on the overall survival (OS) of patients with triple-negative breast cancer (TNBC), and to analyze the relationships of CXCL13 with infiltration degree of tumor-infiltrating lymphocytes (TIL) and the expression of common immune checkpoints.

Methods The transcriptome sequencing results and clinical data of TNBC patients in the cancer Genome Atlas database were downloaded, and the relationship between CXCL13 expression and OS in TNBC patients was analyzed. The biological function of CXCL13 in TNBC was excavated by Gene-set Enrichment Analysis (GSEA); the Tumor Immune Estimation Resource (TIMER) database was used to analyze the correlations of the expression level of CXCL13 with TIL infiltration degree and the expression of common immune checkpoints in TNBC.

Results CXCL13 was significantly highly expressed in TNBC (P < 0.001), and its expression level was significantly correlated with OS of patients (P < 0.05). Results of GSEA showed that the high expression of CXCL13 in TNBC was able to activate key immune-related pathways. TIMER database analysis showed that CXCL13 was significantly positively correlated with the infiltration degree of TIL and the expressions of common immune checkpoints such as programmed death receptor 1, programmed death receptor ligand 1 and cytotoxic T lymphocyte associated protein 4 at in TNBC patients (P < 0.001).

Conclusion CXCL13 is a prognostic factor for patients with TNBC, and may play an important role in immunotherapy of TNBC.