High CXCR4 expression correlates with sunitinib poor response in metastatic renal cancer.

Background: Almost 30% of the sunitinib-treated patients for metastatic renal carcinoma (mRCC) do not receive a clinical benefit. Convincing evidences demonstrated a cross talk between the VEGF and CXCR4 pathways. It was hypothesized that CXCR4 expression in primary renal cancer could predict sunitinib responsiveness. Patients and Methods: In this exploratory study sixty-two mRCC patients receiving sunitinib as first-line treatment were evaluated for CXCR4 expression through immunohistochemistry (IHC). Correlations between CXCR4 expression, baseline patients and tumour characteristics were studied by contingency tables and the chi-square test. Univariable analysis was performed with the log-rank test, and the Cox model was applied for multivariable analysis. Results: The objective response rate of sunitinib first-line therapy was 35.5% (22/62) with a disease control rate (response and stable disease) of 62.9% (39/62). CXCR4 expression was absent/low in 30 (48.4%), moderate in 17 (27.4%), and high in 15 (24.2%) tumors respectively. Low or absent CXCR4 expression predicted response to sunitinib therapy. Moreover, Fuhrman grading and concomitant, CXCR4 and Fuhrman grading, strongly predicted sunitinib first line therapy responsiveness on progression-free survival and overall survival. Conclusions: High CXCR4 expression correlates with sunitinib poor response in metastatic renal cancer