The SDF-1/CXCR4 pathway has been suggested as a target for renal cancer therapy (Reckamp et al, 2008), and dose-dependent increases in SDF-1 levels have been reported previously in normal nontumour-bearing mice treated with sunitinib in a previous study (Ebos et al, 2007), which further supports our results. The gene discussed is CXCL12; the disease is renal carcinoma.