- Eschbacher, Kathryn;
- Tran, Quynh;
- Moskalev, Evgeny;
- Jenkins, Sarah;
- Fritchie, Karen;
- Stoehr, Robert;
- Caron, Alissa;
- Link, Michael;
- Brown, Paul;
- Guajardo, Andrew;
- Brat, Daniel;
- Wu, Ashley;
- Santagata, Sandro;
- Louis, David;
- Brastianos, Priscilla;
- Kaplan, Alexander;
- Alexander, Brian;
- Rossi, Sabrina;
- Ferrarese, Fabio;
- Raleigh, David;
- Nguyen, Minh;
- Gross, John;
- Velazquez Vega, Jose;
- Rodriguez, Fausto;
- Perry, Arie;
- Martinez-Lage, Maria;
- Orr, Brent;
- Haller, Florian;
- Giannini, Caterina
Meningeal solitary fibrous tumors (SFT) are rare and have a high frequency of local recurrence and distant metastasis. In a cohort of 126 patients (57 female, 69 male; mean age at surgery 53.0 years) with pathologically confirmed meningeal SFTs with extended clinical follow-up (median 9.9 years; range 15 days-43 years), we performed extensive molecular characterization including genome-wide DNA methylation profiling (n = 80) and targeted TERT promoter mutation testing (n = 98). Associations were examined with NAB2::STAT6 fusion status (n = 101 cases; 51 = ex5-7::ex16-17, 26 = ex4::ex2-3; 12 = ex2-3::exANY/other and 12 = no fusion) and placed in the context of 2021 Central Nervous System (CNS) WHO grade. NAB2::STAT6 fusion breakpoints (fusion type) were significantly associated with metastasis-free survival (MFS) (p = 0.03) and, on multivariate analysis, disease-specific survival (DSS) when adjusting for CNS WHO grade (p = 0.03). DNA methylation profiling revealed three distinct clusters: Cluster 1 (n = 38), Cluster 2 (n = 22), and Cluster 3 (n = 20). Methylation clusters were significantly associated with fusion type (p < 0.001), with Cluster 2 harboring ex4::ex2-3 fusion in 16 (of 20; 80.0%), nearly all TERT promoter mutations (7 of 8; 87.5%), and predominantly an SFT histologic phenotype (15 of 22; 68.2%). Clusters 1 and 3 were less distinct, both dominated by tumors having ex5-7::ex16-17 fusion (respectively, 25 of 33; 75.8%, and 12 of 18; 66.7%) and with variable histological phenotypes. Methylation clusters were significantly associated with MFS (p = 0.027), but not overall survival (OS). In summary, NAB2::STAT6 fusion type was significantly associated with MFS and DSS, suggesting that tumors with an ex5::ex16-17 fusion may have inferior patient outcomes. Methylation clusters were significantly associated with fusion type, TERT promoter mutation status, histologic phenotype, and MFS.