PT - JOURNAL ARTICLE AU - E Pierce AU - R Doshi AU - R Deane TI - PCNA and Ki-67 labelling indices in pre-irradiated and post-irradiated astrocytomas: a comparative immunohistochemical analysis for evaluation of proliferative activity. AID - 10.1136/mp.51.2.90 DP - 1998 Apr 01 TA - Molecular Pathology PG - 90--95 VI - 51 IP - 2 4099 - http://mp.bmj.com/content/51/2/90.short 4100 - http://mp.bmj.com/content/51/2/90.full SO - Mol Pathol1998 Apr 01; 51 AB - AIM: To determine the tumour proliferative activity in a series of archival cerebral astrocytomas and compare proliferating cell nuclear antigen (PCNA) and Ki-67 labelling indices in the primary and recurring neoplasms following therapeutic radiation. METHOD: Twenty eight cases of pre-irradiated and post-irradiated astrocytomas (ranging from WHO grades I to IV) were stained immunohistochemically using the avidin-biotin horseradish peroxidase technique. Two antibodies, PC10 and MIB-1, were used to establish the proliferating labelling indices, PC10 identifies PCNA and MIB-1 recognises the Ki-67 antigen. RESULTS: Both antibodies showed significantly higher labelling indices in the post-irradiated specimens. However, in general, the Ki-67 indices were lower than those for PCNA. MIB-1 immunoreactivity showed less variation and was more intense than that seen with PC10. The discrepancy between the labelling indices of the pre-irradiated and post-irradiated samples raises questions about the evolution of astrocytomas and the effects of therapeutic intervention. CONCLUSIONS: The data may represent genetic alterations, the natural tumour course, and/or the effect of radiation. Although both of the antibodies reflected the state of growth of neoplastic cells in astrocytomas, MIB-1 was more reliable. A simple immunohistochemical method using proliferation markers does have an important role in the future care of patients with astrocytoma.