Expression of aldolase C isozyme in renal cell carcinoma.

The authors localized aldolase C in renal tubules and renal cell carcinoma by immunohistochemical study and quantitative analysis by an enzyme immunoassay. Aldolase C was localized in epithelial cells of loops of Henle and collecting ducts and in those of Bowman's capsules. In renal cell carcinoma, aldolase C was immunohistochemically demonstrated in 95% (41 of 43) of cases, including one sarcomatoid variant. The tissue concentrations of aldolase C in the renal cortex (n = 8) were 12.7 +/- 6.2 micrograms/g protein (mean +/- standard deviation), and those of the medulla (n = 8) were 20.3 +/- 6.9 micrograms/g protein. On the other hand, the concentrations in renal cell carcinoma (n = 26) were 93.5 +/- 95.9 micrograms/g protein: about seven times higher than that in renal cortex (P less than 0.001). These findings indicate that aldolase C was first expressed in renal cell carcinoma, which is derived from proximal renal tubules, because proximal renal tubules had aldolase B but not aldolase C.