Decreases of metallothionein and aminopeptidase N in renal cancer tissues

Good molecular markers for investigating the biochemical differences betwee n renal cancer and surrounding tissues have not yet been developed. Sixteen kidney samples (clear cell RCC) were investigated to determine the differe nces in the protein components between renal cancer and surrounding tissues , using HPLC analysis. The metallothionein (MT) and zinc levels were consis tently lower in renal cancer tissues compared with in surrounding tissues. The mean concentration of MT in normal tissues surrounding renal tumors was about 15 times higher than that in cancer tissues. An immunohistochemical study confirmed that the expression of MT in renal cancer tissues was lower than that in adjacent normal tissues. The activities of aminopeptidases (A Ps) were significantly decreased in renal cancer tissues compared with in a djacent normal tissues. An immunohistochemical study and Western blot analy sis confirmed that the expression of AP-N in renal cancer tissues was also lower than in adjacent normal tissues. These results suggest that the immun ohistochemical detection of MT and AP-N could provide useful information as a pathological diagnostic tool for classifying renal cancer and surroundin g tissues.