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Co-deletion of 1p/19q as Prognostic and Predictive Biomarker for Patients in West Bohemia with Anaplastic Oligodendroglioma.

BACKGROUND
Anaplastic oligodendrogliomas (AO) are rare tumors. Two phase III clinical trials (RTOG 9402 and EORTC 26951) proved favorable effects of radiotherapy (RT) with chemotherapy (procarbazine, lomustine and vincristine; PCV) in patients with AO carrying chromosomal mutation of co-deletion1p/19q even if it was not the primary endpoint of these studies. We assessed 1p/19q co-deletion as a prognostic and predictive biomarker for our patients with AO.


MATERIALS AND METHODS
1p/19q co-deletion was assessed by fluorescence in situ hybridization in tumor samples from 23 patients and correlated with progression-free (PFS) and overall (OS) survival for the entire cohort and for the subgroups of patients with different treatment (neurosurgery plus RT alone vs. RT plus PCV).


RESULTS
1p/19q co-deletion was identified in 12 out of 23 tumors (52.2%). Patients with co-deletion had longer OS (587 vs. 132 weeks, p=0.012) and a trend for longer PFS (321 vs. 43 weeks, p=0.075). Patients with co-deletion treated with neurosurgery and RT plus PCV vs. neurosurgery and RT alone also had longer OS (706 vs. 423 weeks, p=0.008). There was no survival difference for patients without 1p/19q co-deletion in relation to treatment.


CONCLUSION
The prognostic value of 1p/19q co-deletion in our patients with AO was verified. The strong positive predictive value of this biomarker for OS was also shown for patients with co-deletion treated with neurosurgery and RT plus PCV vs. neurosurgery and RT alone.