A Classification of Tumor Development Based on an Analysis of Enzymes in Tissue Sections of Hypernephroid Carcinoma in Man

Abstract

Sections of hypernephroid carcinoma from 20 cases were investigated for aldolase isozymes A and B by a mixed aggregation immuno-cytochemical technique, and for the brush border membrane enzymes aminopeptidase and alkaline phosphatase by conventional histochemical techniques. It was found that the cases could be grouped into four types: type 1 (1 case) contained all 4 enzymes; type 2 (7 cases) contained all enzymes except aldolase-B; type 3 (7 cases) possessed aldolase-A and one brush border membrane enzyme; type 4 (5 cases) contained only aldolase-A. The aldolase-A concentration in all tumor cells was higher than that in proximal tubule cells, whereas the concentration of the two brush border enzymes was lower. In cases tydolase-B and/or higher amounts of the brush border enzymes than the surrounding cells. No correlation was observed between clear cell and granular cell hypernephroid carcinomas or the invasiveness or the nuclear polymorphism of the tumors on the one hand with their enzyme type on the other. These histological enzyme analyses suggest that most, if not all, hypernephroid carcinomas are derived from kidney proximal tubule cells and that the tumor cells then progressively lose aldolase-B, and subsequently the brush border enzymes, but at the same time producing more aldolase-A. The presence of the enzyme-rich patches suggest different patterns of proliferation and differentiation among the tumor cell population. Three tumors other than hypernephroid carcinoma were also examined in this way. The results suggest that histoenzymological analyses are of general applicability in studies of tumor progression. They should also be useful for biopsy and aspiration cytology.