These results indicate that p53 mutations are a genetic hallmark of gemistocytic astrocytomas, whilst PTEN mutations are absent in low-grade and rare in anaplastic gemistocytic astrocytomas.
These results indicate that p53 mutations are a genetic hallmark of gemistocytic astrocytomas, whilst PTEN mutations are absent in low-grade and rare in anaplastic gemistocytic astrocytomas.
In this study, gemistocytes and non-gemistocytic neoplastic cells were separated by laser-assisted microdissection from six gemistocytic astrocytomas carrying TP53 mutations.
Gemistocytic astrocytoma is characterized by a predominance of large astrocytes with plump processes and massive accumulation of glial fibrillary acidic protein (gemistocytes).
DNA sequencing, performed in 84% of cases, revealed that TP53 mutations were most frequent in gemistocytic astrocytomas (88%), followed by fibrillary astrocytomas (53%) and oligoastrocytomas (44%), but were infrequent (13%) in oligodendrogliomas.
LOH 1p/19q typically occurred in tumors without TP53 mutations and were most frequent in oligodendrogliomas (69%), followed by oligoastrocytomas (45%), but were rare in fibrillary astrocytomas (7%) and absent in gemistocytic astrocytomas.
Therefore it appears that GAs should not be uniformly graded as grade II but should be subdivided into grades II and III neoplasms based on histological features and MIB-1 LI.
Therefore it appears that GAs should not be uniformly graded as grade II but should be subdivided into grades II and III neoplasms based on histological features and MIB-1 LI.