Accumulation of p53 and Ki-67 expression do not predict survival in patients with fibrillary astrocytomas or the response of these tumors to radiotherapy.
OBJECTIVE
Although radiotherapy is often used in the treatment of patients with low-grade astrocytomas, its value is still uncertain. Radiotherapy carries a risk of morbidity for patients and has time and cost implications for health services. We have assessed the value of two histological variables, p53 accumulation and Ki-67 expression, in predicting the response of astrocytomas to radiotherapy. The former antigen was assessed because many astrocytic tumors show mutations in the p53 gene, the function of which is crucial for mediating cell death after radiotherapy, and the latter was assessed because it is expressed only in proliferating tumor cells, which may show greater radiosensitivity than nonproliferating cells.


METHODS
Immunohistochemistry was used to detect the accumulation of p53 and expression of Ki-67 in a retrospective series of 96 patients with supratentorial fibrillary astrocytomas, 58 of whom had received postoperative radiotherapy. The immunohistochemical data were correlated with survival after radiotherapy.


RESULTS
There was no significant difference in survival between the patients who did and those who did not receive radiotherapy. The p53 and Ki-67 labeling indices did not correlate with survival in either the irradiated or the nonirradiated cohort, nor with overall survival in the series as a whole.


CONCLUSIONS
Immunohistochemical assessment of p53 accumulation and Ki-67 expression does not help in predicting the survival of patients with supratentorial fibrillary astrocytomas or in predicting whether particular patients are likely to benefit from radiotherapy.
Hilton
D A
DA
Department of Histopathology, Derriford Hospital, Plymouth, England.
Love
S
S
Barber
R
R
Ellison
D
D
Sandeman
D R
DR
D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000378:metabolism* / Q000532:radiotherapy* / Q000601:surgery; D002528:Cerebellar Neoplasms / Q000378:metabolism* / Q000532:radiotherapy* / Q000601:surgery; D002648:Child; D015331:Cohort Studies; D003131:Combined Modality Therapy; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008875:Middle Aged; D011182:Postoperative Care; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53