Molecular landscapes of longitudinal NF2/22q and non-NF2/22q meningiomas show different life histories

Recurrence is a major complication of some meningiomas. Although there were many studies on biomarkers associated with higher grades or increased aggressiveness, few studies specifically examined longitudinal samples of primary meningiomas and recurrences from the same patients for molecular life history. We studied 99 primary and recurrent meningiomas from 42 patients by FISH for 22q, 1q, 1p, 3p, 5q, 6q, 10p, 10q, 14q, 18q, CDKN2A/B homozygous deletion, ALT (Alternative Lengthening of Telomere), TERT re-arrangement, targeted sequencing and TERTp sequencing. Although NF2 mutation and 22q were well known to be aetiological events in meningiomas, we found that in these paired meningiomas, combining the two events resulted in an NF2/22q group (57 tumors from 25 patients) which were almost mutually exclusive with those cases without these two changes (42 tumors from 17 patients) for NF2/22q. No other molecular changes were totally unique to NF2/22q or non-NF2/22q tumors. For molecular evolution, NF2/22q meningiomas had higher cytogenetic abnormalities than non-NF2/22q meningiomas (p = 0.003). Most of the cytogenetic changes in NF2/22q meningiomas were present from the outset whereas for non-NF2/22q meningiomas, cytogenetic events were uncommon in the primary tumors and most were acquired in recurrences. For non-NF2/22q tumors, CDKN2A/B homozygous deletion, 1q gain, 18p loss, 3p loss, and ALT were preferentially found in recurrences. Mutations were largely conserved between primary and recurrent tumors. Phylogenetic trees showed 11/11 patients with multiple recurrent tumors had a conserved evolutionary pattern. We conclude that for molecular life history, NF2 and 22q should be regarded as a group. NF2/22q recurring meningiomas showed more cytogenetic abnormalities in the primary tumors, whereas non-NF2/22q meningiomas showed CDKN2A/B deletion and other cytogenetic abnormalities and ALT at recurrences. Although chromosome 1p loss is a known poor prognostic marker in meningiomas, it was also associated with a shorter TBR (time between resection) in this cohort (p = 0.002).