Correlation of tumor p53 and PCNA with response and survival of glioblastoma in patients treated with an ECOG protocol of pre-irradiation chemotherapy.

BACKGROUND

The ability to predict treatment responsiveness and survival of patients with glioblastoma multiforme, the most malignant and most common primary brain tumor, would be a valuable asset. Tumor and proliferation markers such as p53 and PCNA have been immunohistochemically defined and have been useful in other tumors in determining prognosis. Therefore, the authors studied the correlation of responsiveness to treatment, time to progression and survival with p53 and PCNA labeling indices in a pre-irradiation chemotherapy study of the glioblastoma multiforme.

METHODS

Immunohistopathology for labeling indices for p53 and PCNA using formalin-fixed, paraffin-embedded tissue from the glioblastomas of 23 patients entered into a phase II ECOG trial of pre-irradiation chemotherapy were defined using the streptavidin-peroxidase technique with AEC chromogen. The labeling indices were correlated with response to treatment time to progression and overall survival. Most patients received three cycles of BCNU for three days over three months and cisplatin monthly for three days over three months prior to external beam irradiation.

RESULTS

There were no significant differences in treatment response, time to progression or overall survival in glioblastoma, patients with positive p53 labeling index (> 5%) versus a negative p53 labeling index (< or = 5%) or positive PCNA labeling (> 10%) versus a negative labeling index (< or = 10%) or any combination of P53 and PCNA labeling indices.

CONCLUSIONS

Using this protocol of pre-irradiation chemotherapy, p53 and PCNA labeling indices in the glioblastoma multiforme did not predict treatment benefit.