Role of p53 Immunohistochemistry in Differentiating Reactive Gliosis From Malignant Astrocytic Lesions

Abstract

P53 immunohistochemistry has been used to distinguish between malignant tumors and morphologically similar benign processes. In the central nervous system, a major diagnostic dilemma is caused by overlapping features of benign reactive astrocytic lesions and low-grade astrocytomas, especially with small biopsies. P53 immunoreactivity in astrocytes could be useful in differentiating benign reactive lesions from malignant astrocytomas. An immunohistochemical study on 110 brain lesions from 108 patients using a monoclonal antibody (DO-7) against p53 protein was conducted. Using the modified Ringertz and World Health Organization system, the specimens included 22 astrocytomas, 12 anaplastic astrocytomas, 42 glioblastoma multiforme tumors, three nonglial tumors, and 56 reactive astrocytic lesions to 25 neoplasms, nine infectious processes, six cerebrovascular disorders,one metabolic disorder, two vascular malformations, eleven degenerative/demyelinating lesions, and two unknown primary lesions. Immunoreactive astrocytic tumors included 12 (54%) astrocytomas, nine (75%) anaplastic astrocytomas, and 38 glioblastoma multiforme tumors (90%). Among the reactive astrocytic lesions, only five (9%) cases of progressive multifocal leukoencephalopathy were immunoreactive. These data demonstrate that p53 immunoreactivity in astrogliosis is unusual but is to be expected in astrocytomas and can help to differentiate reactive from neoplastic astrocytic lesions.

Índice de astrócitos gemistocíticos e imuno-expressão da proteína p53 em astrocitomas, grau II e III OMS

“…Apenas pequeno número de trabalhos avaliou imuno-expressão da proteína p53 ou mutação do gene correspondente em astrocitomas, com especificação do subtipo gemistocítico ou com discriminação de gemistocitos 9,11,17,[21][22][23][24] .…”

“…Em discordância com os resultados da presente série, os estudos de Yaziji et al 21 , VITAL et al 23 , Rathore et al 24 relatam frequência de 100% de positividade da p53 em astrocitomas gemistocíticos. Entretanto, as casuística são pequenas e há diferenças de ordem técnica.…”

Oligoastrocytoma: A Vanishing Tumor Entity

“…No specific immunohistochemical marker was available for oligodendrocytes [17,18], although MAP2, OLIG2, Cyclin D1, and alpha-internexin (INA) immunopositivity could be found in the oligodendroglial component. Approximately one third of OAs showed nuclear p53 accumulation, more commonly in the astrocytic cells [19].…”

Diagnostic and prognostic significance of cyclin A expression in low-grade astrocytomas: comparison with astrogliosis and high-grade tumours

“…For example, there is a significant overlap in the Ki-67 labelling index (LI) for radiation damage astrogliosis (<1–10%) and recurrent astrocytic gliomas (<1–40%) 2. While overexpression of p53 is generally detected in about half of astrocytomas, in line with the finding of gene mutations in approximately 60% of diffuse lesions (World Health Organization (WHO) grade II), lack of immunostaining does not appear to be helpful for exclusion of any possibility of malignancy 3 – 5…”