Concomitant CXCR4 and CXCR7 Expression Predicts Poor Prognosis in Renal Cancer

CXCR4 is a chemokine receptor implicated in the metastatic process. The CXCR4 ligand, CXCL12, was shown to bind the CXCR7 receptor also, a recently deorphanized chemokine receptor whose signalling pathway and function are still controversial. This study was conducted to determine patients clinic-pathological factors and outcome according to the expressions of CXCR4 and CXCR7 in renal cell carcinoma (RCC). CXCR4 and CXCR7 expression were evaluated in 223 RCC patients through immunohistochemistry; moreover CXCR4 and CXCR7 were detected in 49 other consecutive RCC patients through RT-PCR. CXCR4 expression was low in 42/223 RCC (18,8%), intermediate in 71/223 (31,9%) and high in 110/223 (49,3%). CXCR7 expression was low in 44/223 RCC patients (19,8%), intermediate in 65/223 (29,1%) and high in 114/223 (51,1%). High CXCR4 and high CXCR7 expression predicted shorter disease free survival. In multivariate analysis, high CXCR4 expression (p= 0.0061), high CXCR7 (p= 0.0194) expression and the concomitant high expression of CXCR4 and CXCR7 (p= 0.0235) are independent prognosis factors. Through RT-PCR, CXCR4 was overexpressed in 36/49 and CXCR7 in 33/49 samples correlating with symptoms at diagnosis and lymph nodes status. So we can hypothesize that CXCR4 and CXCR7, singularly evaluated and in combination, are valuable prognostic factors in RCC patients.