[Allelic loss at 1p/19q analysis in brain tumors of glial lineage]

To analyze in cerebral tumors of neuroepithelial tissue 1p/19q codeletions by study of loss of heterozygosity (LOH). A first implied objective was to get ready this molecular thecnique.

We aimed to determine several deletions mapping 1p and 19q chromosomes, three allelic loss of 1p and two allelic loss of 19q, in patients with cerebral tumors which were operated in our Department from October 2004 until March 2006. We have detected in blood and tumoral DNA loss of heterozygosity assay for molecular detection using PCR and capillary array electrophoresis of five markers (D1S508, D1S2734, D1S199, D19S412 y D19S219).

Were included in the first part of this study 45 sample of neuroepithelial tissue supratentorial tumors: 29 glioblastoma, 1 gliosarcoma, 7 diffuse astrocytoma grade II, 1 oligoastrocytoma, 3 oligodendroglioma, 1 anaplastic oligodendroglioma, 1 xanthoastrocytoma, 1 dysembryoplastic neuroepithelial tumour and 1 pilocytic astrocytoma. We considered deleted regions identified when allelic ratio (T1/T2)/( N1/N2) was lower than 0.8. 80% of oligodendroglial tumors, 14% glioblastoma and 14% of diffuse astrocytoma grade II.

Evaluation of 1p/19q allelic status by LOH analysis may provide useful information for guiding clinical and therapeutical decisions with high succes ratio. These results shown why patients with 1p/19q codeletion survive longer, because adjuvant alkylants adds further improvements to standard, surgery and radiotherapy, treatments.