Molecular genetic analysis as a tool for evaluating stereotactic biopsies of glioma specimens.

Over the last years, distinct genetic lesions have been associated with individual tumor entities. Stereotactic biopsy has become an essential diagnostic tool in surgical neuro-oncology. In order to evaluate the potential of molecular analyses in stereotactic biopsies, we examined a series of 156 human brain tumors from patients undergoing stereotactic biopsy for molecular alterations typically seen in astrocytic gliomas and compared those results with a control group of 268 astrocytic tumors obtained at open surgery.

PTEN mutations in gliomas and glioneuronal tumors.

Cytogenetic and loss of heterozygosity studies have suggested the presence of at least one tumor suppressor gene on chromosome 10 involved in the formation of high grade gliomas. Recently, the PTEN gene, also termed MMAC1 or TEP1, on chromosomal band 10q23 has been identified. Initial studies revealed mutations of PTEN in limited series of glioma cell lines and glioblastomas.

Analysis of the PTEN gene in human meningiomas.

Previous observations demonstrated that the neurofibromatosis type 2 gene (NF2) plays an important role in the pathogenesis of the transitional, fibroblastic and malignant variants of human meningiomas. No specific genes have been associated with the pathogenesis of meningothelial meningiomas and with the progression to anaplastic meningiomas. However, allelic losses on chromosomal arms 1p, 10q and 14q have been implicated in the process of malignant progression.

Molecular genetic evidence for subtypes of oligoastrocytomas.

The histogenesis of oligoastrocytomas remains controversial, with some data arguing similarity of oligoastrocytomas to astrocytic tumors, and other data suggesting closer relationships with oligodendroglial neoplasms. Since the molecular genetic changes in astrocytomas differ from those of oligodendrogliomas, we characterized 120 astrocytic and oligodendroglial tumors, including 38 oligoastrocytomas, for genetic alterations that occur disproportionately between astrocytomas and oligodendrogliomas, i.e.

Molecular genetic analysis of giant cell glioblastomas.

Glioblastomas (GBMs) are a heterogeneous group of tumors. Recently, distinct molecular genetic alterations have been linked to subgroups of patients with GBM. Giant cell (gc)GBMs are a rare variant of GBM characterized by a marked preponderance of multinucleated giant cells.