I m a g e C y t o m e t r i c M e a s u r e m e n t o f N u c l e a r P r o l i f e r a t i o n M a r k e r s ( M I B -1 , P C N A ) i n A s t r o c y t o m a s1 " 3 For astrocytomas, the proliferative capability of the neoplasm becomes increasingly important because of the confines of the skull and the rapidity of the onset of symptoms as the tumor enlarges. Additional insight into the behavior of astrocytomas has been gained by evaluating the proliferative activity for individual neoplasms. This approach is especially important when assessment of proliferation can overcome biopsy sampling inadequacies in which histologic criteria are not readily evident or are difficult to determine.Research into proliferation markers for astrocytomas has included several approaches, including analysis of variance showed a significant correlation between the histologic grade and MIB-1 and between the histologic grade and PCNA. The Cox Proportional Hazards Regression Model showed a statistically significant correlation between survival and MIB-1 and between survival and PCNA. Increasing proliferation correlated with shortened survival. Proliferation in astrocytomas, measured as MIB-1 and PCNA by image cytometry, correlates significantly with histologic grade and patient survival, providing useful additional information for determining the diagnosis and prognosis.