Glioblastomas with oligodendroglial component - common origin of the different histological parts and genetic subclassification.
BACKGROUND
Glioblastomas are the most common and most malignant brain tumors in adults. A small subgroup of glioblastomas contains areas with histological features of oligodendroglial differentiation (GBMO). Our objective was to genetically characterize the oligodendroglial and the astrocytic parts of GBMOs and correlate morphologic and genetic features with clinical data.


METHODS
The oligodendroglial and the "classic" glioblastoma parts of 13 GBMO were analyzed separately by interphase fluorescence in situ hybridization (FISH) on paraffin sections using a custom probe set (regions 1p, 1q, 7q, 10q, 17p, 19q, cen18, 21q) and by comparative genomic hybridization (CGH) of microdissected paraffin embedded tumor tissue.


RESULTS
We identified four distinct genetic subtypes in 13 GBMOs: an "astrocytic" subtype (9/13) characterized by +7/-10; an "oligodendroglial" subtype with -1p/-19q (1/13); an "intermediate" subtype showing +7/-1p (1/13), and an "other" subtype having none of the former aberrations typical for gliomas (2/13). The different histological tumor parts of GBMO revealed common genetic changes in all tumors and showed additional aberrations specific for each part.


CONCLUSIONS
Our findings demonstrate the monoclonal origin of GBMO followed by the development of the astrocytic and oligodendroglial components. The diagnostic determination of the genetic signatures may allow for a better prognostication of the patients.
Klink
Barbara
B
Institut für Klinische Genetik, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. barbara.klink@tu-dresden.de
Schlingelhof
Ben
B
Klink
Martin
M
Stout-Weider
Karen
K
Patt
Stephan
S
Schrock
Evelin
E
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000145:classification / Q000235:genetics* / Q000473:pathology*; D005260:Female; D005909:Glioblastoma / Q000145:classification / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000145:classification / Q000235:genetics* / Q000473:pathology*