Defining a prognostic score based on O6-methylguanine-DNA methyltransferase cut-off methylation level determined by pyrosequencing in patients with glioblastoma multiforme.
J Neurooncol 2018;
140:559-568. [PMID:
30132165 DOI:
10.1007/s11060-018-2981-7]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 08/14/2018] [Indexed: 02/06/2023]
Abstract
PURPOSE
Epigenetic variations in the O6-methylguanine-methyltransferase gene had been widely associated with a favorable impact on survival in patients affected by glioblastoma multiforme (GBM). Aim of this study is to explore a scoring system based on the gene promoter methylation in order to predict patients' prognosis.
METHODS
A series of 128 patients with GBM was retrospectively analyzed. A training set and a validations set were then generated. The methylation level of CpGi from 74 to 83 was determined by pyrosequencing. In accordance to previous literature, each island was assigned with 1 point if the corresponding methylation level was higher than 9%. The sum consisted in a score that went from 0 (all CpGi < 9%) to 10 (all CpGi ≥ 9%). A threshold capable to detect a favorable outcome (overall survival, OS > 24 months) was identified by ROC analysis.
RESULTS
Median OS and follow-up were 14 and 32.6 months respectively. Among the total population, 35% of the pts had a score of 0, while 29% had a score of 10. A score ≥ 6 was associated with a favorable prognosis also when corrected for age (> 70 vs. ≤ 70 years) and ECOG performance status (0-1 vs. 2-3). Similar results were observed also in terms of PFS. Results were consistent in the training and in the validation set.
CONCLUSIONS
The present manuscript explored a novel scoring system capable to take into consideration the methylation status of each single CpGi, capable to better predict prognosis in GBM patients.
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