Phosphohexose isomerase activity as a tumor marker in hepatoma bearing rats (Yoshida A.H. 130)

The object of this study was to examine if there exists, analogously to what happens in human cancer patients, elevation of phosphohexose isomerase activity (PHI, EC 5.3.1.9) in the serum of animals bearing an experimental tumor and, if so, whether such increases were related to the progress of the tumor, as in humans. The behavior of the same enzyme activity within the tumor itself was also studied. Significant correlations were found between serum elevations of PHI and hepatoma growth. These correlations, moreover, emerge at a very early stage. On the other hand, no relation appears to exist between phosphohexose isomerase activity in the tumor and that in the blood. The two divisions, furthermore, do not seem to interact. These results may prove interesting prospectives for the monitoring of human cancer.