MPTH-10MOLECULAR-GENETIC AND CLINICAL RISK FACTORS FOR PATIENTS WITH GLIOMAS WITH TOTAL 1p19q LOSS

Abstract

Codeleted gliomas are associated with better response to therapy and longer survival. However, early recurrence occurs at times, and there are cases with short survival despite 1p19q loss. Although several unfavorable prognostic factors are known for low grade gliomas, the risk factors for patients with codeleted gliomas has not been elucidated. We studied 57 codeleted tumors of WHO grade II-III for chromosomal copy number abnormality (CNA) by comparative genomic hybridization (metaphase CGH), promoter methylation of the MGMT gene by methylation-specific PCR as well as clinical factors known to be associated with prognosis of glioma patients. Overall survival (OS) curves were estimated using the Kaplan-Meier method, and compared by grade (grade 2 versus grade 3), age (patients from 50 years up versus under 50 years of age, ), extent of surgery (over 95% removal versus partial removal versus biopsy), tumor maximum diameter (larger than 5cm diameter versus less), copy number abberations detected in more than 10% of all cases, status of MGMT methylation and pathological diagnosis by original institutional diagnosis (oligodendroglial versus astrocytic). As a result, there was no significant difference in OS for age, extent of surgery, maximum tumor diameter, histological feature and status of MGMT methylation. On the other hand, the OS was significantly shorter in the patients with gliomas with gain of 19p (p = 0.011), and gain on 17q and histological grade III showed trends towards poor prognosis (p = 0.055, 0.1, respectively).In conclusion, gain of 19p, gain on 17q, and histological grade III might be unfavorable prognostic factors of gliomas with total 1p19q loss.