Expression of P53 and Ki-67 in different grades of astrocytomas

Abstract

Article informationBackground: Astrocytomas are considered the most prevalent central nervous system [CNS] tumors. Diffuse astrocytomas are evaluated by a three-tiered system [II, III, and IV] according to the 2007 WHO classification. The WHO grading scheme is based on the existence or lack of four histological features: mitosis, nuclear atypia, microvascular proliferation, and necrosis. Pilocytic astrocytoma is classified as WHO grade I in histological grading of localized astrocytic tumors. In many cases of human neoplasms, including astrocytoma, p53, and Ki67, the expression increases, especially in aggressive and highgrade tumors. The Aim of the work:We aimed to validate the p53 and Ki 67 immunohistochemical expression in various grades of astrocytic tumors and correlate this expression with clinicopathologic findings and histopathologic grading. Patients and methods: Immunohistochemical analysis [IHC] of p53 and Ki67 were used to evaluate 45 paraffin-embedded samples, which included different grades of astrocytoma [10 participants of pilocytic astrocytoma, 12 participants of diffuse astrocytoma grade II, 9 participants of anaplastic type, and 14 participants of glioblastoma type]. Tumor tissue blocks and clinical information of the cases were gathered from the files of Pathology Department of Al-Azhar University Hospitals [Al-Hussein & Al-Zahraa] and from the archives of some private laboratories from March 2018 to June 2021. Results: Immunohistochemical [IHC] expression of p53 and Ki 67 had a significant positive association with histopathological grading of astrocytoma. High expressions were detected in high-grade astrocytoma [grade III, IV] versus low-grade types [I, II]. Conclusion: p53 and Ki 67 immunohistochemical expression is up regulated in high-grade astrocytoma. Their overexpression seems to indicate a more malignant phenotype.