Use of CXCR4 expression to predict the efficacy of sorafenib treatment in patients with metastatic renal cell carcinoma.

Abstract

359 Background: CXCR4, a chemokine receptor, is implicated in the metastastic process. Higher expression of CXCR4 in renal cell carcinoma predicts shorter disease-free survival and poorer prognosis. This study aims to investigate the relationship of CXCR4 expression with the efficacy of target drugs in treatment of metastatic renal cell carcinoma (mRCC). Methods: A total of 58 patients with mRCC treated with target drugs (26 with sorafenib, 23 with sunitinib, 5 with pazopanib, 2 with CCI-779, and 2 with axitinib) as the first-line therapy in Beijing Cancer Hospital between 2006 and 2010 were investigated. CXCR4 expression in tissue was detected by immunohistochemistry. Survival curves were estimated according to the Kaplan-Meier method and evaluated with the Log-rank test. The correlation of CXCR4 expression with Memorial Sloan-Kettering Cancer Center criteria (MSKCC) was assessed with χ2 test. p < 0.05 was considered statistically significant. Results: CXCR4 expression was negative in 6.9% (4/58) of patients, low in 19.0% (11/58) of patients, intermediate in 56.9% (33/58) of patients and high in 17.2% (10/58) of patients, which was not correlated with MSKCC (p = 0.143). The PFS of patients with negative or low CXCR4 expression (20.0 ± 5.9 months) was longer than those with intermediate or high expression (8.5 ± 1.3 months), which, however, was not statistically different (p = 0.131). The PFS of sorafenib-treated patients with negative or low CXCR4 expression was 20.0±8.0 months while the patients with intermediate or high CXCR4 expression was 6.0 ± 0.8 months (p = 0.038). No such correlation existed in the group of patients treated with sunitinib (p = 0.947). And median OS had not been achieved yet. Conclusions: CXCR4 can predict the efficacy of sorafenib treatment in mRCC patients. Patients with negtive or low CXCR4 expression are more likely to obtain longer PFS than those with intermediate or high CXCR4 expression. [Table: see text]