In search for new, more useful biomarkers to diagnose RCC or to improve prognosis we aimed to determine the (dys-)balance of an endogenous inhibitor of matrix metalloproteinases (MMPs) and an inducer of MMPs, namely reversion-inducing cysteine-rich protein with Kazal motifs (RECK) and extracellular matrix metalloproteinase inducer (EMMPRIN, CD147), which we have shown to be responsible for a dysbalance in urothelial carcinoma of the bladder [6]. The gene discussed is RECK; the disease is renal cell carcinoma.