Survival analysis was restricted to the group of diffuse astrocytomas (48 patients). pRb expression did not correlate with histological type, grade or p53 expression, while a moderately strong correlation existed between pRb expression and the percentages of proliferating cell nuclear antigen (PCNA) and MIB-1-positive cells.
Paraffin-embedded surgical specimens from 56 human astrocytomas (8 pilocytic [I degree] astrocytomas, 9 low grade [II degrees] fibrillary astrocytomas, 9 high grade [III degrees] astrocytomas and 30 glioblastomas) were immunostained with the anti-PCNA, anti-p53, anti-Ki-67 and anti EGFR antibodies.
Both the EGFR expression and PCNA labeling index increase with increasing grades of astrocytomas with a significantly high percentage of cells showing positive staining for both EGFR and PCNA in GBM and Grade III astrocytomas compared to Grade II astrocytomas.