Tumor M2 pyruvate kinase in renal cell carcinoma. Patient plasma examination

Tumor cell metabolism is characterized by a high rate of aerobic glycolysis . The metabolic differences require changes in glycolytic enzyme activities and isoenzyme patterns. The inactive form of the M2 pyruvate kinase (Tu M2 -PK) is specifically expressed in tumor cells and has been detected immunoh istochemically in tumor tissue but also in peripheral blood of patients wit h different malignant tumors. In this study,Tu MZ-PK in the plasma of patie nts with renal cell carcinoma (RCC) was compared with healthy volunteers. T u M2-PK was quantified with a commercially available enzyme linked immunoso rbent assay (ELISA) kit. Using the ELISA kit, plasma probes of 57 healthy i ndividuals were compared to 63 patients with RCC (51 patients with non-meta static RCC, 12 patients with metastatic RCC). Statistical analysis was perf ormed with the non-parametric ANOVA test according to Kruskal-Wallis. In pa tients with renal cell carcinoma,Tu M2-PK was significantly higher than in healthy volunteers. For organ-defined, non-metastatic tumors, sensitivity w as only 27.5%, if the 95% reference values of the control group were used f or discrimination. The differences were more pronounced in patients with me tastatic disease. Tu M2-PK was significantly enhanced compared to healthy c ontrols, but also to the group with non-metastatic disease, the sensitivity was 66.7%. Our data show that Tu M2-PK has no impact as an unspecific mark er for the diagnosis of renal cell carcinoma. This is especially relevant t o organ-defined, non-metastatic RCC. In advanced metastatic disease, a pote ntial importance as a parameter for treatment control in palliative therape utic approaches can be assumed, and warrants further investigations.