Gustav Y. Cederquist

PURPOSE: To determine whether driver gene alterations in metastatic non–small cell lung carcinoma (NSCLC) spine metastases are associated with local tumor control after radiotherapy (RT). METHODS: Patients with NSCLC who underwent RT for spine metastasis and tumor genetic profiling were ascertained. Associations between driver gene mutations incidence of local failure were analyzed, followed by competing risk analysis for significant associations. The results were validated using in vitro clonal survival assays of CRISPR-engineered NSCLC cell lines. RESULTS: A total of 181 patients were analyzed, with a median follow-up of 15.2 months (IQR, 8.0-31.9 months). The 3-year risk of local failure was 0.15 (95% CI, 0.10 to 0.20). Patients harboring NF1 or BRAF driver alterations experienced higher 3-year local failure rates ( NF1 : 0.33 [0.09-0.61] v 0.13 [0.09-0.19]; P = .002); BRAF : 0.31 [0.08-0.57] v 0.13 [0.09-0.19]; P = .04). NF1 loss-of-function mutations conferred radioresistance in one of two NSCLC cell lines tested in vitro. Based on the convergence of NF1 and BRAF signaling, the RAS- mitogen-activated protein kinase ( MAPK ) pathway was further interrogated. KRAS mutations overall were not associated with local failure. However, comutation of KRAS / TP53 exhibited a trend toward elevated 3-year local failure, 0.31 (0.11-0.55) versus 0.13 (0.08 v 0.19), P = .05. RAS-MAPK pathway driver alterations accounted for 53% of all local failures ( P < .0001) and showed an elevated 3-year risk of local failure (0.36 [0.2-0.51] v 0.09 [0.05-0.15]; P < .001), including when treated with stereotactic body RT (0.28 [0.1-0.5] v 0.05 [0.02-0.11]; P = .001). CONCLUSION: Driver alterations in the RAS-MAPK signaling pathway confer radioresistance in metastatic NSCLC. These genetic alterations may serve as biomarkers to personalize RT strategies or as targets to enhance radiosensitivity.

Consolidation for primary central nervous system lymphoma (PCNSL) after induction chemoimmunotherapy include whole-brain radiotherapy (WBRT; ≤24 Gy reduced-dose [RD], >24 Gy standard-dose) and cytarabine, nonmyeloablative chemotherapy (NMC), or autologous hematopoietic cell transplantation (AHCT). Comparative outcomes are lacking. Outcomes from 1983-2020 were stratified by decade and Memorial Sloan Kettering Cancer Center recursive partitioning analysis (RPA) class. Clinicodemographic associations were analyzed by multinomial logistic regression. Progression-free survival (PFS) and overall survival (OS) were analyzed by proportional hazards. Of 559 patients, 385 (69%) were consolidated. Median follow-up and OS were 7.4 and 5.7 years, respectively. WBRT use declined (61% (1990s) vs 12% (2010s)), whereas AHCT (4% (1990s) vs 32% (2010s)) and NMC (27% (1990s) vs 52% (2010s)) rose. Compared with RPA 1, RPA 2 was more likely to receive NMC. Those with partial response to induction were less likely to receive AHCT (odds ratio, 0.36; P = .02). Among 351 with complete response to consolidation, only receipt of rituximab, methotrexate, procarbazine, and vincristine induction was associated with improved PFS (hazard ratio, 0.5; P = .006). Among RPA 1, median PFS and OS were not reached for AHCT or RD-WBRT, vs 2.5 and 13.0 years, respectively, after NMC. Among RPA class 3, median PFS and OS after RD-WBRT were 4.6 and 10 years, vs 1.7 and 4.4 years after NMC. No significant adjusted survival differences were seen across consolidation strategies. NMC is increasingly used in lieu of RD-WBRT despite a trend toward less favorable PFS. RD-WBRT can be considered in patients ineligible for AHCT.

Despite the litany of pathogenic variants linked to neurodevelopmental disorders (NDD) including autism (ASD) and intellectual disability ^1,2 , our understanding of the underlying mechanisms caused by risk genes remain unclear. Here, we leveraged a human pluripotent stem cell model to uncover the neurodevelopmental consequences of mutations in ZMYND11 , a newly implicated risk gene ^3,4 . ZMYND11, known for its tumor suppressor function, encodes a histone-reader that recognizes sites of transcriptional elongation and acts as a co-repressor ^5,6 . Our findings reveal that ZMYND11-deficient cortical neural stem cells showed upregulation of latent developmental pathways, impairing progenitor and neuron production. In addition to its role on histones, ZMYND11 controls a brain-specific isoform switch involving the splicing regulator RBFOX2. Extending our findings to other chromatin-related ASD risk factors revealed similar developmental pathway activation and splicing dysregulation, partially rescuable through ZMYND11’s regulatory functions.

Chimeric antigen receptor (CAR) T-cell therapy (CART) for central nervous system lymphoma (CNSL) is a promising strategy, yet responses are frequently not durable. Bridging radiotherapy (BRT) is used for extracranial lymphoma in which it can improve CART outcomes through cytoreduction of high-risk lesions. We hypothesized that BRT would achieve similar, significant cytoreduction before CART for CNSL (CNS-BRT). We identified patients with CNSL with non-Hodgkin B-cell lymphoma who received CNS-BRT before commercial CART. Cytoreduction from CNS-BRT was calculated as change in lesion size before CART. Twelve patients received CNS-BRT, and the median follow-up among survivors is 11.8 months (interquartile range, 8.5-21.9). Ten patients had CNSL (9 secondary, 1 primary) and 2 patients had epidural disease (evaluable for toxicity). All 10 patients with CNSL had progressive disease at the time of CNS-BRT. Of 12 patients, 1 experienced grade ≥3 cytokine release syndrome, and 3 of 12 patients experienced grade ≥3 immune effector cell–associated neurotoxicity syndrome. CNS-BRT achieved a 74.0% (95% confidence interval, 62.0-86.0) mean reduction in lesion size from baseline (P = .014) at a median of 12 days from BRT completion and before CART infusion. Best CNS response included 8 complete responses, 1 partial response, and 1 progressive disease. Three patients experienced CNS relapse outside the BRT field. Preliminary data suggest CNS-BRT achieves rapid cytoreduction and is associated with a favorable CNS response and safety profile. These data support further study of BRT as a bridging modality for CNSL CART.

BACKGROUND: Survival duration and prognostic factors in adult high-grade glioma have been comprehensively analyzed, but less is known about factors contributing to overall survival (OS) and progression-free survival (PFS) in pediatric patients. OBJECTIVE: To identify these factors in the pediatric population. METHODS: We retrospectively reviewed institutional databases evaluating all patients ≤21 years with high-grade glioma treated between 1988 and 2010. Kaplan-Meier curves and log-rank statistics were used to compare groups univariately. Multivariate analyses were completed using Cox proportional hazards regression models. RESULTS: Ninety-seven patients were identified with a median age of 11 years. Median OS was 1.7 years, and median PFS was 272 days. Location was significant for OS (P < .001). Patients with gross total resection (GTR) had a median OS of 3.4 years vs 1.6 years for subtotal resection and 1.3 years for biopsy patients (P < .001). Female patients had improved OS (P = .01). Female patients with GTR had a mean OS of 8.1 years vs 2.4 years for male patients with GTR and 1.4 years for all other female patients and male patients (P = .001). PFS favored patients ≤3 and ≥13 years and females (P = .003 and .001). CONCLUSION: OS was significantly correlated with the location of the tumor and the extent of resection. GTR significantly improved overall survival for both glioblastoma multiforme and anaplastic astrocytoma patients, and female patients showed a much larger survival benefit from GTR than male patients. ABBREVIATIONS: AA, anaplastic astrocytoma GBM, glioblastoma multiforme GTR, gross total resection HGG, high-grade glioma OS, overall survival PFS, progression-free survival STR, subtotal resection WHO, World Health Organization

The mammalian neocortex is parcellated into anatomically and functionally distinct areas. The establishment of area-specific neuronal diversity and circuit connectivity enables distinct neocortical regions to control diverse and specialized functional outputs, yet underlying molecular controls remain largely unknown. Here, we identify a central role for the transcriptional regulator Lim-only 4 (Lmo4) in establishing the diversity of neuronal subtypes within rostral mouse motor cortex, where projection neurons have particularly diverse and multi-projection connectivity compared with caudal motor cortex. In rostral motor cortex, we report that both subcerebral projection neurons (SCPN), which send projections away from the cerebrum, and callosal projection neurons (CPN), which send projections to contralateral cortex, express Lmo4, whereas more caudal SCPN and CPN do not. Lmo4-expressing SCPN and CPN populations are comprised of multiple hodologically distinct subtypes. SCPN in rostral layer Va project largely to brainstem, whereas SCPN in layer Vb project largely to spinal cord, and a subset of both rostral SCPN and CPN sends second ipsilateral caudal (backward) projections in addition to primary projections. Without Lmo4 function, the molecular identity of neurons in rostral motor cortex is disrupted and more homogenous, rostral layer Va SCPN aberrantly project to the spinal cord, and many dual-projection SCPN and CPN fail to send a second backward projection. These molecular and hodological disruptions result in greater overall homogeneity of motor cortex output. Together, these results identify Lmo4 as a central developmental control over the diversity of motor cortex projection neuron subpopulations, establishing their area-specific identity and specialized connectivity.

Microtubules are essential components of axon guidance machinery. Among β-tubulin mutations, only those in TUBB3 have been shown to cause primary errors in axon guidance. All identified mutations in TUBB2B result in polymicrogyria, but it remains unclear whether TUBB2B mutations can cause axon dysinnervation as a primary phenotype. We have identified a novel inherited heterozygous missense mutation in TUBB2B that results in an E421K amino acid substitution in a family who segregates congenital fibrosis of the extraocular muscles (CFEOM) with polymicrogyria. Diffusion tensor imaging of brains of affected family members reveals aberrations in the trajectories of commissural projection neurons, implying a paucity of homotopic connections. These observations led us to ask whether axon dysinnervation is a primary phenotype, and why the E421K, but not other, TUBB2B substitutions cause CFEOM. Expression of exogenous Tubb2b-E421K in developing callosal projection neurons is sufficient to perturb homotopic connectivity, without affecting neuronal production or migration. Using in vitro biochemical assays and yeast genetics, we find that TUBB2B-E421K αβ-heterodimers are incorporated into the microtubule network where they alter microtubule dynamics and can reduce kinesin localization. These data provide evidence that TUBB2B mutations can cause primary axon dysinnervation. Interestingly, by incorporating into microtubules and altering their dynamic properties, the E421K substitution behaves differently than previously identified TUBB2B substitutions, providing mechanistic insight into the divergence between resulting phenotypes. Together with previous studies, these findings highlight that β-tubulin isotypes function in both conserved and divergent ways to support proper human nervous system development.

Molecular controls over the development of the exceptional neuronal subtype diversity of the cerebral cortex are now beginning to be identified. The initial subtype fate decision early in the life of a neuron, and the malleability of this fate when the balance of key postmitotic signals is modified, reveals not only that a neuron is deterministically set on a general developmental path at its birth, but also that this program must be precisely executed during postmitotic differentiation. Here, we show that callosal projection neurons (CPN) and subcerebral projection neurons (subcerebral PN) in layer V of the neocortex share aspects of molecular identity after their birth that are progressively resolved during differentiation. The LIM-homeodomain–related genes Lmo4 and Clim1 are initially expressed by both CPN and subcerebral PN in layer V, and only during mid to late differentiation does expression of Lmo4 and Clim1 become largely segregated into distinct neuronal subtypes. This progressive postmitotic resolution of molecular identity reveals similarities and possibly shared evolutionary origin between layer V CPN and subcerebral PN, and provides insight into how and when these neuronal subtypes achieve their distinct identities during cortical development.