AQP1 and renal cell carcinoma: Comparative proteomics analysis of urinary exosomes from RCC patients and healthy controls identified several urinary exosomal protein markers, amongst which 10 were validated by Western blot analysis, including matrix metalloproteinase-9 (MMP-9), ceruloplasmin (CP), podocalyxin (PODXL), Dickkopf-related protein 4 (DKK 4), carbonic anhydrase IX (CAIX), aquaporin-1 (AQP-1), neprilysin (CD10), dipeptidase 1 (DPEP1), extracellular matrix metalloproteinase inducer (EMMPRIN), and syntenin-1 [178].