High expression of CX3CL1 by tumor cells correlates with a good prognosis and increased tumor‐infiltrating CD8+ T cells, natural killer cells, and dendritic cells in breast carcinoma

BACKGROUND: CX3CL1 is the only CX3C chemokine that can chemoattract T cells, natural killer (NK) cells, and dendritic cells (DCs). The role of CX3CL1 in breast carcinoma remains unknown. METHODS: Immunohistochemical staining for CX3CL1, CD8, CD57, and CD1a was performed on 204 breast carcinoma specimens using tissue microarray blocks to determine whether CX3CL1 expression correlated with a good prognosis and antitumor immunity. RESULTS: The number of stromal CD8+ T cells, intratumoral CD1a+ DCs, and stromal CD57+ NK cells were significantly increased in the high CX3CL1 expression group compared with those in the low CX3CL1expression group. Patients with high CX3CL1 expression had a significantly better disease-free and overall survival than those with low CX3CL1 expression (P=0.002 and P<0.001, respectively). CX3CL1 expression was identified as one of the independent prognostic factors for disease-free and overall survival (P=0.046 and P=0.010, respectively). CONCLUSION: The expression of CX3CL1 by tumor cells appears to enhance the recruitment of CD8+ T cells, CD57+ NK cells, and CD1a+ DCs, thereby bringing about a better prognosis in breast carcinoma. CX3CL1 is a new prognostic biomarker and may be a novel candidate for development of a more effective therapeutic strategy for breast carcinoma.