They found that matrix metalloproteinase 9 (MMP9), copper cyanine (Cp), podocalyxin (PC), DKK 4, and carbonic anhydrase IX (CAIX) were significantly enriched in RCC, while Aquaporin-1 (AQP-1), extracellular matrix metalloproteinase inducer (EMMPRIN), enkephalinase (CD10), dipeptidyl peptidase 1 and Syntenin-1 expression were significantly decreased. Here, MMP9 is linked to renal cell carcinoma.