PCNA and Ki-67 labelling indices in pre-irradiated and post-irradiated astrocytomas: a comparative immunohistochemical analysis for evaluation of proliferative activity.
OBJECTIVE
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.


METHODS
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.
Pierce
E
E
School of Chemical and Life Sciences, University of Greenwich, London, UK.
Doshi
R
R
Deane
R
R
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D002455:Cell Division; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen