Tertiary lymphoid structures marker CXCL13 is associated with better survival for patients with advanced-stage bladder cancer treated with immunotherapy

Immune checkpoint inhibitors (ICIs) have proved to be an effective treatment for up to 40% of muscle-invasive bladder cancer (MIBC), but there is still a need for better performing biomarkers allowing to improve prediction of response to ICI. Response to immunotherapy in soft-tissue sarcoma, melanoma and renal cell carcinoma have been recently linked to the presence of tertiary lymphoid structures (TLS) in the tumour. TLS are organised aggregates of T, B and dendritic cells, participating in adaptive antitumor immune response. The chemokine CXCL13 is involved in the formation of TLS, and is reported as a reliable transcriptomic marker of TLS. In this study, we sought to assess whether CXCL13 transcript expression can be a prognostic biomarker for ICI-treated MIBC patients and also investigated whether it can serve a biomarker of TLS in MIBC. We analysed transcriptomic data from three publicly available MIBC cohorts and evaluated pathological slides from the TCGA-BLCA cohort for TLS presence and stage of maturation. We showed that CXCL13 was independently associated with both prolonged survival (HR = 0.8, 95% CI [0.68–0.94]) and objective response (p