Real-time quantification of the proliferative state in astrocytomas

OBJECTIVE: To evaluate proliferative activity in a set of gliomas and to co mpare the quantitative data obtained by a real-time processor with the labe lling index (LI) and mitotic index (MI). STUDY DESIGN: Ki-67 immunostaining was performed on paraffin-embedded speci mens from 42 cases of glioblastomas, 17 cases of anaplastic astrocytomas an d 14 cases of low grade astrocytomas. Nuclear positivity was calculated as LI and by a real-time image processor for quantitative evaluation MI was al so calculated at 10 high-power fields. The data obtained from glioblastomas were compared with those from anaplastic and low grade astuocytomas. To al l the data was applied the Pearson test to verify the correlation between c ounting and quantitative values and between proliferative markers and survi val. RESULTS: A positive trend from low grade astrocytomas to glioblastomas was found for Ki-67 (LI and quantitative values) and MI, with highly significan t differences between the three grades of gliomas considered. A good correl ation between LI and quantitative values of Ki-67 was found. Very little re lationship resulted between survival and Ki-67 LI. No relationship was foun d between survival and quantitative values of Ki-67. CONCLUSION: Ki-67 allowed effective separation of astrocytic tumors with di fferent grades of malignancy. Quantitative evaluation of color information by means of a real-time processor proved to be a useful, objective and fast way to obtain readings, useful for grading purposes but not for prognostic evaluation.