Proliferative potential of brain tumors. Analyses with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine labeling, and nuclear organizer region counts.

Histochemical analyses with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies were done, and argyrophilic nucleolar organizer regions (Ag-NOR) were counted to estimate the proliferative potential of 200 brain tumors. The findings were compared with the bromodeoxyuridine labeling index (BrdU LI), or S-phase fraction. The proliferating cell indexes (PCI), determined by Ki-67 and anti-DNA polymerase alpha monoclonal antibodies were higher and Ag-NOR more numerous in medulloblastomas, glioblastomas, and metastatic carcinomas than in astrocytomas or meningiomas. The Ki-67 and DNA polymerase alpha PCI correlated with the BrdU LI (r = 0.87 and r = 0.84, respectively) and with each other (r = 0.94). The number of Ag-NOR correlated less strongly with these indexes in some tumors. These findings suggest that Ki-67 and anti-DNA polymerase alpha monoclonal antibodies may be useful for estimating the proliferative potential of individual tumors in routine clinical practice. The number of Ag-NOR, however, does not always reflect the growth potential of each tumor.