Value of tumor M2 (Tu M2-PK) in patients with renal carcinoma

Pyruvate kinase is one of the glycolytic key enzymes. It exists in various isoforms which 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. The Tu M2-PK concentration was measured in EDTA-plasma of 116 patients with renal carcinoma and 42 patients suffering from nephritis, by using this kit. 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 correlated strongly with the Robson tumor stage of the 116 patients. The present results indicated that the Tu M2-PK might be the first tumor marker, which could be an excellent complementation of the diagnostic program for renal carcinoma.