Simultaneous Alterations of Retinoblastoma and p53 Protein Expression in Astrocytic Tumors

Annapurna RATHORE1, Pacchapam KAMARAJAN1, Meera MATHUR1, Subrata SINHA2, Chitra SARKAR1

1Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
2Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India


The genetic alterations frequently involved in glial malignancies are in the tumor suppressor genes, Rb and p53. An altered Rb expression or p53 overexpressions is thought to indicate defective tumor supression and subsequently more aggressive tumors. Therefore, to assess the alterations in the conjoint expression of Rb and p53 proteins in formalin fixed paraffin embedded sections, 64 astrolytic tumors were studied (16 astrocytomas, 7 gemistocytic astrocytomas, 19 anaplastic astrocytomas and 22 glioblastomas) using the avidin biotin immunoperoxidase technique. Fifty two cases (81.25%) were found to be positive for p53 protein. Seventeen of these showed aberrant heterogenous staining for pRb, of which 7 were glioblastomas. Only one case of astrocytoma showed aberrant expression of both p53 and Rb. Thus, of the 64 tumors, simultaneous aberrant expression of both p53 and Rb was seen in 21.9% of cases. This was more commonly observed among glioblastoma cases (7/22). No statistical difference was found between the survival rate of heterogenous pRb and p53 positivity in different grades of tumors. In glioblastomas, the survival rate appeared to be less in patients expressing heterogenous pRb, but this was not statistically significant. These results lead us to suspect that p53 and pRb pathways are inactivated, either throught mutation or as part of the neoplastic process in astrocytic tumors. Pathology & Oncology Research, Vol 5, Nr 1, 21-27, 1999

Key words: astrocytic tumors, p53, pRb, immunochemistry, survival

Received: Dec 9, 1998; accepted: Jan 15, 1999
Correspondence: Chitra SARKAR, Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029, India; Tel: +91-011-6593371, Fax: +91-011-6862663; E-mail:

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