Changes in serum CXCL13 levels are associated with outcomes of Colorectal Cancer Patients Undergoing First-Line Oxaliplatin-Based Treatment

Abstract Background Reliable biomarkers for precision medicine in metastatic colorectal cancer (mCRC) are needed. Blood biomarkers like chemokines may offer insights into overall tumor burden, yet, few prospective studies explore chemokine dynamics during treatment. This study investigates the behavior of a chemokine panel in mCRC patients during first-line oxaliplatin-based treatment, aiming to identify predictive and prognostic biomarkers. Methods Blood from oxaliplatin-treated mCRC patients was collected at three time points: before treatment (PRET), at response evaluation (EVAR), and at disease progression or last follow-up (LFUP). A custom 11-chemokine panel assessed serum chemokine levels by Luminex®, correlating them with treatment response, overall survival (OS), and progression-free survival (PFS) using the Cox proportional hazards models with the inverse probability weighting (IPW) approach. Additionally, immune system-associated gene expression was studied by Nanostring® in 15 primary tumor samples and correlated with CXCL13 expression, OS, and PFS. In silico analysis of 119 liver metastases from CRC patients, post neoadjuvant oxaliplatin-based treatment or untreated, evaluated CXCL13 expression’s correlation with immune cell infiltration, tertiary lymphoid structure (TLS) presence, OS, and PFS. Additionally, CXCL13 dynamics was studied by ELISA in 36 mCRC patients from the METIMMOX study control arm. Results Responders exhibited increased CXCL13 at EVAR, contrasting with non-responders whose levels decreased at EVAR and LFUP. Increased CXCL13 independently associated with improved PFS (median 14.5 vs. 8.9 months; HR = 0.34, p = 0.003) and OS (median 39.7 vs. 15.3 months; HR = 0.34, p = 0.003). CXCL13 expression correlated positively with an immunogenic tumor microenvironment, increased B cells, T cells (mainly CD8+) and enhanced OS. In silico , higher CXCL13 expression associated significantly with increased immune infiltration and improved OS. High CXCL13 expression was linked to the presence of TLSs, also associated with enhanced OS, especially in neoadjuvant-treated patients. Similar trends were obtained using the METIMMOX cohort. Conclusion The increase of CXCL13 levels in peripheral blood and its association with the formation of TLSs within the metastatic lesions, emerges as a potential biomarker indicative of the therapeutic efficacy in metastatic CRC patients undergoing oxaliplatin-based treatment.