Among these proteins, the expression of MMP9, ceruloplasmin (CP), podocalyxin like (PODXL), carbonic anhydrase IX (CAIX) and dickkopf 4 (DKK4) in urinary exosomes was higher in patients with kidney cancer than that in normal patients, and the expression of CD10, extracellular matrix metalloproteinase inducer (EMMPRIN), dipeptidase 1 (DPEP1), syntenin 1 and aquaporin 1 (AQP1) in urinary exosomes was higher in normal patients than that in patients with kidney cancer. This evidence concerns the gene MMP9 and kidney cancer.