BIOM-43. THE GENOMIC, TRANSCRIPTOMIC, AND EPIGENOMIC LANDSCAPE OF ISOCITRATE DEHYDROGENASE WILD TYPE GLIOBLASTOMA ACROSS THE AGE CONTINUUM

BACKGROUND

Older age is a poor prognostic factor for glioblastoma (GBM) patients. We tested whether the intrinsic molecular landscape of the tumor may contribute to this poor prognosis.

METHODS

In accordance with the 2021 WHO classification scheme, we included only isocitrate dehydrogenase (IDH) wild type GBM. Based on published literature, we defined older as age > 65. RNA expression, gene amplification, tumor mutational burden (TMB) and mutational profiles were analyzed in three unique datasets: Tempus (n = 1,410), Caris (n = 1,432), and TCGA (n = 557). Comparison were made between < 65 and ³ 65 year olds using Pearson’s Chi-squared tests, Fisher’s exact tests, or Wilcoxon rank-sum where appropriate.

RESULTS

From our evaluable gene sets, TERT promoter mutations were more prevalent in patients ³ 65 years old (Caris 82.64 vs 77.27%, p = 0.016; Tempus 58.0 vs 49.0%, p = 0.002). There were no significant differences in PDCD1, CD274, CD3E, TNFRSF18, CD40, CD8A, TNFRSF4, CTLA4, HAVCR2, TNFSF9, CD274, or CDKN2A; PDL-1 (by IHC); dMMR/MSI-H, TMB; CDK6 amplification, EGFR amplification, EGFR, EGFRvIII, EGFR fusions, MET fusions, PTEN, TP53, or NF-1. MGMT promoter methylation (Caris data) was more common in the older group (49.73 v 34.14%, p < 0.001). TGCA data demonstrated that gene expression, TMB, and methylation did not change significantly with age. Additionally, PCOLCE2 and SLC10A4 were differentially methylated, and missense mutations, of any type, were more common in the older group (p=0.006).

CONCLUSION

Despite worse survival outcomes for older patients with IDHwt GBM as compared to younger counterparts, the molecular landscape is similar at the genomic, transcriptomic and epigenomic levels. The key exception is TERT promoter mutations that are more common in older GBM patients. Poorer survival is therefore not likely to be attributable solely to intratumoral factors.

Articular fractures of the fingers in children

Articular fractures of the fingers in children may result in severe sequelae that impair function of the hand. All displaced fractures must be reduced and fixed. Undisplaced fractures must be securely immobilized (including neighboring joints) and checked frequently for a possible displacement. Even when tested properly, articular fractures may have an unsatisfactory outcome.

Irreversibly sickled cell beta-actin: defective filament formation

It has been demonstrated that cysteine modification in irreversibly sickled cell beta-actin slows down the remodeling of membrane skeletons [Shartava et al.: J Cell Biol 128:805-812, 1995]. This slow remodeling can be due to alterations in spectrin-actin binding and/or actin-actin interactions in irreversibly sickled cell (ISC) membrane skeletons. In these studies we demonstrate that ISC actin binds spectrin normally. However, ISC beta-actin polymerizes and depolymerizes more slowly than control beta-actin, and forms unusual aggregates when placed under polymerizing conditions. Electron microscopic analysis of actin polymers indicated that ISC actin generates a large amount of aggregates which we conclude are due to the structural modification caused by the disulfide bridge between cysteine284 and cysteine373 in beta-actin.