Expression of CXCL10 and CXCL16 in Triple-Negative Breast Cancer and Their Association with Immunotherapy Efficacy and Prognosis.

BACKGROUND: Triple-negative breast cancer (TNBC) represents the most aggressive breast cancer subtype with limited therapeutic options. This study investigated the expression patterns of chemokines CXCL10 and CXCL16 in TNBC and their association with immunotherapy response and clinical outcomes. METHODS: We retrospectively analyzed 128 TNBC patients treated at our institution between 2019-2023. CXCL10 and CXCL16 expressions were assessed by immunohistochemistry. Sixty-eight patients received immune checkpoint inhibitor (ICI)-based therapy. The primary endpoints were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). RESULTS: High CXCL10 expression (≥50% positive cells) was observed in 72 patients (56.25%), while high CXCL16 expression was found in 65 patients (50.78%). In the immunotherapy cohort, patients with high CXCL10 expression demonstrated significantly higher ORR (44.44% vs 18.75%, p=0.024) and longer median PFS (8.62 vs 4.35 months, HR=0.467, 95% CI: 0.268-0.814, p=0.007). Combined high expression of both chemokines showed the most favorable outcomes, with ORR of 52.63% and median PFS of 10.84 months. Multivariate Cox regression confirmed CXCL10 (HR=0.512, p=0.008) and CXCL16 (HR=0.623, p=0.032) as independent prognostic factors for PFS. CONCLUSION: CXCL10 and CXCL16 expression levels are associated with improved immunotherapy response and favorable prognosis in TNBC and may serve as candidate predictive biomarkers. Combined assessment of both chemokines may optimize patient selection for ICI-based therapy. Prospective validation in larger cohorts is warranted.