Macrophage colony-stimulating factor-1 receptor expression is associated with poor outcome in breast cancer by large cohort tissue microarray analysis

Purpose: Macrophage colony-stimulating factor-1 receptor (CSF-1R) is a transmembrane tyrosine kinase receptor, which is abnormally expressed in invasive breast cancer. Small cohort studies have demonstrated that increased expression of CSF-1R is associated with ipsilateral breast cancer recurrence. Correlation with survival has not been reported. Our aim was to further evaluate the role of CSF-1R in breast cancer, by studying the expression of CSF-1R in a large cohort of clinical specimens. Experimental Design: Tissue microarrays containing 301 node-negative and 280 node-positive cases were used. Immunohistochemical staining was performed and correlated with overall survival, nodal status, and other clinicopathological data. Results: CSF-1R expression was strongly associated with nodal status. Of the node-negative cases, 114 (38.9%) stained positive for CSF-1R, whereas 189 (67.5%) of the node-positive cases expressed CSF-IR (P < 0.0001). CSF-IR expression is also associated with larger tumor size (P = 0.02). Positive staining was strongly associated with decreased survival (P = 0.0003). Among node-negative patients, CSF-1R expression was associated with decreased overall survival (P = 0.045), whereas among node-positive patients, it was not (P = 0.47). In multivariate analysis, CSF-1R was not independent of nodal status as a predictor of survival. Conclusions: CSF-1R expression is a strong predictor of poor outcome in nonmetastatic breast cancer. It is significantly more frequently expressed in patients with nodal involvement. Among the node-negative patients, it has a stronger association with survival than among the nodepositive patients. Our findings support other preclinical findings that CSF-1R may be involved in local invasion and metastasis. Thus, this receptor may be an effective target for therapeutic agents.