Degree of enhancement of polyamine biosynthetic decarboxylase activities in human tumors: a useful new index of degree of malignancy.

We have determined the levels of L-ornithine decarboxylase (ODC) and S-adenosyl-L-methionine decarboxylase (AMD) in 134 untreated human primary tumors, such as skin epitheliomas and brain tumors. The levels of both decarboxylases increase in proportion to the grade of malignancy (ascertained by histologic criteria) in both the basal cell and squamous cell carcinomas of the skin. In the various types of brain tumors, ODC levels are more reliable indications of the grade of malignancy than AMD levels. In fact, the highest ODC levels observed in medulloblastoma and in astrocytoma grade IV were not associated with similarly high AMD levels. The same dichotomy between the levels of the two decarboxylases was observed for meningiomas, in which ODC levels were higher in atypical forms (with karyokinesis) then in typical forms (without karyokinesis).