The pyruvate kinase isoenzyme tumor M2 (Tu M2-PK) as a tumor marker for renal carcinoma.

Various isoforms of the glycolytic enzyme pyruvate kinase are expressed in different cell-types. One of these isoforms, the type Tu M2-PK, is strongly overexpressed by tumor cells and released into body fluids. The concentration of Tu M2-PK in body fluids can be quantitatively determined by a commercially available enzyme-linked immunosorbent assay (ELISA)-kit. Using this kit, the Tu M2-PK concentration was measured in EDTA-plasma of 64 patients with renal carcinoma and 10 patients suffering from nephritis. The ranges of the Tu M2-PK-concentrations of the two groups did not overlap, indicating a highly significant discrimination of renal carcinoma and benign renal diseases. Furthermore, the Tu M2-PK-concentration in EDTA-plasma correlates strongly with the Robson tumor stage of the 64 patients. The present results indicate that the Tu M2-PK might be the first tumor marker which could be an excellent complementation of the diagnostic program for renal carcinoma.