ABNORMALITIES OF THE SERUM ENZYME ACTIVITY ASSOCIATED
WITH RENAL CELL CARCINOMA WITH SPECIAL REFERENCE TO THE ALKALINE PHOSPHATASE
1976 Volume 67 Issue 11 Pages 941-947
Details
1976 Volume 67 Issue 11 Pages 941-947
Though it was well documented that renal cell carcinoma was frequently associates with an increase of serum alkaline phosphatase activity, no precise explanation of its origin has been offered. There are two possibilities about it, namely, a release of the enzyme from tumor cells into the circulating blood, and an elevation of serum alkaline phosphatase due to hepatic dysfunction caused by cytotoxic metabolites from the cancer tissue.
The author investigated the origin of the increased enzyme activity through the experimental methods, i. e. renal blood flow study and isoenzyme analysis. In the former study, the renal vein blood flow was determined by means of local thermodilution technique and the activities of enzymes (ALP and LDH) both of the renal vein and artery specimens were measured. When veno-arterial difference of enzyme activity was multiplied by renal plasma flow, the value means the amount of the enzyme releases from the kidney. In six cases of renal cell carcinoma thus investigated, the amount of enzymes released from the tumor-bearing kidney far exceeded those of the contralateral kidney.
In the latter study, isoenzyme patterns of the serum alkaline phosphatase were analysed by means of cellulose acetate electrophoresis. Of 15 patients analysed, eleven showed a normal ALP activity and four showed a significant elevation of it. In patients with a normal activity, the isoenzyme pattern displayed a light band of ALP-2, which was to be expected in healthy subjects. Of four cases with an elevation, three showed an intense band at ALP-2, which suggested to be hepatocellular origin. One remaining patient showed a markedly high serum ALP level (128.8 K-A units), where the isoenzyme analysis identified heat-stable ALP-4. Neverthless, the heat-stable ALP was not detected anywhere of the removed kidney, neither histochemically nor biochemically.
The results of these two studies were apparently contradictory, because the detailed pathway remained obscure. But, changes of several enzymes in courses of renal carcinoma were not negligible in diagnosis and in clinical persuit of the disease. Detection and separation of specific carcinogenic isoenzymes are to be expected because of their early diagnosis and recognition.
