'The Reports of My Death Are Greatly Exaggerated'-Evaluating the Effect of Necrosis on Promoter Methylation Testing in High-Grade Glioma.

(1) Background: (O-6-methylguanine-DNA methyltransferase) promoter methylation remains an important predictive biomarker in high-grade gliomas (HGGs). The influence of necrosis on the fidelity of promoter (p) hypermethylation testing is currently unknown. Therefore, our study aims to evaluate the effect of varying degrees of necrosis on p status, as determined by pyrosequencing, in a series of primary and recurrent HGGs; (2) Methods: Within each case, the most viable blocks (assigned as 'true' MGMTp status) and the most necrotic block were determined by histopathology review.