Staging and Prognosis  

Proc. Int. Symp. "New Treatments for Brain Tumors: Gene Therapy and Neural Stem Cells". Parma, Italy, October 17-20, 2001. Abstract No. P-1 (Report on Prognostic Factors)

Meeting Abstract

Allelic losses on chromosomes 1p, 19q, 17p and 10q as predictors of survival in oligoastrocytomas

Bissola L, Eoli M, Merciai B, Silvani A, Salsano E, Broggi G, Boiardi A and Finocchiaro G

Istituto Nazionale Neurologico Besta, Milano, Italy.

Oligoastrocytomas are mixed gliomas consisting of varying proportions of astrocytic and oligodedrocytic cells: genetically they are only partially characterized. 
Oligodendogliomas often show coincident loss of heterozigosity (LOH) on chromosome 1p and19q and these markers are associated with a good prognosis, possibly related to sensitivity to chemotherapy. 
LOH on 17p occurs in approximately one third of malignant astrocytomas, and has been linked to the formation of secondary glioblastomas. 
LOH on 10q is present in a fraction of anaplastic astrocytomas but is highly frequent in glioblastomas. 
To contribute to the genetic characterization of mixed gliomas and to look for clinical correlations we have investigated LOH by amplification of different microsatellites on 1p, 19q, 17p and 10q on lymphocyte and tumor DNA from 34 oligoastrocytomas (9 grade II OA and 25 grade III AnOA).
In all tumors investigated at least one marker was informative. 
LOH for 1p was found in 15 cases, LOH for 19q in12 cases (9 of them were associated with LOH on 19q), LOH for 10q in 7 cases and LOH for 17 p in 6 cases.
The alterations on 1p, 17p, 10q were never associated. 
Patients with LOH on 10q had a shorter survival compared to all the other patients (p = 0.0024) and the poor prognosis appeared indipendent from other clinical parameters affecting survival. 
Correlations with losses on 1p and 17q require a longer follow-up for statistical evaluation, but a trend for longer survival seems associated with 1p and 19q losses. 
The data support the use of genetic analysis to help the clinical management of mixed gliomas.