The Role of CXCL13 and CXCL9 in Early Breast Cancer

Background
Chemokines, cytokines in the immune microenvironment of tumors, may be associated with patient outcome. We assessed the impact of CXCL13 and CXCL9 on disease-free (DFS) and overall survival (OS), in an attempt to retrospectively evaluate both T and B cell function in the microenvironment of primary tumors from patients with breast cancer.
Materials and Methods
Formalin-fixed paraffin-embedded tissue blocks from patients with intermediate/high-risk, early breast cancer, treated with sequential adjuvant epirubicin, paclitaxel, and cyclophosphamide methotrexate fluorouracil within a randomized trial, were tested for CXCL13 and CXCL9 messenger RNA expression; 557 patients with adequate tissue were eligible for the analysis.
Results
CXCL13 was correlated with CXCL9 (rho = 0.52; P < .001). High-expressing CXL13 and CXCL9 tumors had higher Ki67 and tumor infiltrating lymphocyte density ( P -values < .001). High CXCL9 expression was an unfavorable prognosticator for OS among all patients (hazard ratio [HR], 1.73; P = .021), whereas it showed favorable significance for both DFS and OS in patients with triple negative disease (HR, 0.29; P = .027 and HR, 0.32; P = .045). High CXCL13 conferred longer DFS and OS among patients with luminal-human epidermal growth factor receptor 2 disease (HR, 0.31; P = .013 and HR, 0.25; P = .005). Patients with low CXCL13 and high CXCL9 expression had shorter DFS and OS compared with those with high expression of both chemokines (HR, 1.63; P = .006 and HR, 1.61; P = .016).
Conclusions
Both biomarkers were associated with poor prognosis characteristics and with tumor infiltrating lymphocyte density. High CXCL9 conferred an improved prognosis in the triple negative subtype, whereas high CXCL13 was associated with improved outcome in the luminal-human epidermal growth factor receptor 2 subtype. Chemokines can be associated with breast cancer subtype and outcome. These data should be evaluated prospectively.