Gliomas are the most common
primary brain tumor, and are histopathologically classified according to their cell type and the degree of
malignancy. However, sometimes diagnosis can be controversial,and
tumors of the same entity possibly have a wide range of survival. Genetic analysis of these
tumors is considered to have great importance in terms that it can provide clinically relevant classification of the
tumors and compensate for the limitation of the histological classification. Previous studies using comparative genomic hybridization (CGH) demonstrated that copy number aberrations(CNAs) were frequently recognized in these
tumors, and revealed that a gain on chromosomal arm 7q was the most common CNA in diffuse
astrocytomas, whereas a small population of the
tumor showed losses on 1p/19q which characterizes
oligodendrogliomas with good responsiveness to chemotherapeutic regime using
procarbazine, nitrosourea and
vincristine. High grade (
malignant) gliomas(i.e.
anaplastic astrocytomas,
anaplastic oligodendrogliomas and
glioblastomas) have been reported to have a gain on 7p and losses on 9p and 10q. In case of
ependymomas, frequent
chromosomal aberrations in intracranial
tumors were a gain on 1q and losses on 6q, and, on the other hand, a gain on chromosome 7 was recognized almost exclusively in
spinal cord tumors. These data suggest that intracranial and spinal cord
ependymomas are different
genetic diseases and comprise different subgroups within one histological entity. In conclusion, genetic analysis of
gliomas may help to classify these
tumors and provide leads concerning their initiation and progression. The relationship of these aberrations to patient outcome needs to be addressed.