Integrated analysis of MYC expression, 8q24.21 copy number, and recurrence patterns in astrocytoma, IDH-mutant

Compared to oligodendrogliomas, astrocytomas may have a relatively higher frequency of intracranial remote recurrence, despite generally favorable prognoses. Previous studies identified 8q gain, particularly in the terminal region, as a poor prognostic factor. This study evaluated MYC expression and its relationship with copy number gain at 8q24.21, in relation to recurrence patterns in astrocytomas, with a particular focus on intracranial remote recurrence. A retrospective analysis was conducted on 27 patients treated between 2006 and 2019. MYC expression was assessed by immunohistochemistry (IHC), and copy number status by metaphase comparative genomic hybridization and next-generation sequencing. Recurrence patterns were categorized as local or remote.Among 43 specimens analyzed by IHC, MYC expression was observed in 72%, with higher positivity in recurrent (80%) than initial (61%) specimens, though the difference was not statistically significant (p = 0.30). Copy number analysis showed a significant increase in 8q24.21 copy number in specimens from cases with remote recurrence compared to those with local recurrence (p = 0.033). However, no significant correlation was found between MYC copy number and protein expression (p = 0.055). These findings suggest that MYC is frequently expressed in astrocytomas, but its expression does not significantly reflect 8q gain or recurrence pattern.