Evaluation of creatine kinase isoenzyme BB as a marker of neoplastic growth in Yoshida ascites hepatoma of the rat.

A considerable interest has recently been shown for the measurement of isoenzyme BB of creatine kinase as a diagnostic and prognostic indicator of tumor growth. This isoenzyme belongs to the group of oncofetal antigens and in human cancer elevated levels occur frequently in patients with metastatic disease. In this study we have attempted to quantify CK-BB serum levels during the growth of an experimental tumor (Yoshida Hepatoma AH 130) in male albino rats to determine if a significant correlation exists between isoenzyme serum levels and the rate of tumor growth. Creatine kinase-BB was measured spectrophotometrically by immunoinhibition of creatine kinase-M subunits. CK-BB normal values were 4.19 +/- 0.4 U/L and between days 5 and 9, where there is an increase in the rate of proliferation of neoplastic cells, CK-BB serum levels reaches its maximum 69.01 +/- 2.2 U/L. These data are in agreement with the hypothesis that the highest isoenzyme levels are a measure of the aggressiveness of the neoplastic clone. Moreover, this hypothesis is consistent with the proposed mathematical model, and we plan to expand this line of study to evaluate the predictive potential of this tumor marker in man.