Activity of ornithine decarboxylase (ODC) and polyamine levels as biochemical markers of malignancy in human brain tumors.

The content of the polyamines putrescine, spermidine and spermine, and the activity of their metabolic key enzyme ornithine decarboxylase (ODC) were measured in tissue samples obtained during operation of 45 patients with primary or recurrent gliomas, meningiomas and pituitary adenomas. Biochemical analysis and histopathological classification were carried out in the same tumor samples. In benign tumors ODC activity was less than 10 nmol/g/h, whereas in malignant gliomas values up to 34 nmol/g/h were observed. In rapidly growing tumors pronounced heterogeneity was observed with high values in solid tumor parts and low values in necrotic areas. Thus, high ODC activity represents a reliable biochemical marker of malignancy in brain tumors, but low values do not prove benignity.