Chemokine receptor CXCR4 overexpression predicts recurrence for hormone receptor-positive, node-negative breast cancer patients

Background. The expected outcome for hormone receptor-positive, node-negative patients should be favorable. However, some patients do develop metastatic disease and the mechanism for this observation is poorly understood. CXCR4 is a chemokine receptor that has been implicated to play a pivotal role in breast cancer growth and metastasis. Its predictive role has not been fully evaluated: We determined to see whether CXCR4 can predict outcome in this subset of patients. Methods. We accrued and analyzed data from 101 patients with hormone receptor-positive, node-negative breast cancers. The CXCR4 level was detected using Western blots and its level was defined as either low (<6.6-fold) or high (>= 6.6-fold). Primary end points were systemic cancer recurrence and death. Statistical analysis performed included Spearman's correlation, Kaplan-Meier survival analysis, and Cox proportional hazard model. Results. Although benign breast tissues had an undetectable level of CXCR4, all 101 cancer specimens had overexpressed CXCR4 (mean 6.4 +/- 3.4-fold). There were 79 patients in the low CXCR4 group and 22 patients in the high CXCR4 group. High CXCR4 overexpression was predictive of both cancer recurrence (P = .002) and overall survival (P = .0012). Conclusion. High CXCR4 overexpression in primary tumors was predictive of worse outcomes in hormone receptor-positive, node-negative breast cancer patients. (Surgery 2011;149:193-9.)