Abstract 2623: Targeted therapy with DFMO and immunotherapy equalizes survival in MYCN-amplified neuroblastoma: insights from genomic and network analyses

Abstract Background: This study evaluates the efficacy of difluromethylornithine (DFMO) combined with immunotherapy for its potential as a targeted therapy to mitigate outcome differences associated with MYCN amplification in neuroblastoma (NB). Methods: A clinical trial was conducted involving high-risk (HR) NB patients, who completed standard HR induction and consolidation, were then treated with standard of care immunotherapy adding DFMO either during and/or after immunotherapy. Patients were categorized based on MYCN amplification status. Survival analysis, differential gene expression, and pathway enrichment analyses were performed using RNA sequencing data. STRING and Bayesian network analyses were employed to identify biological relationships among differentially expressed genes (DEGs). Centrality analysis was performed to identify the top nodes in the regulatory network. Cox proportional hazards (CPH) models were used to determine the impact of individual genes on survival, and a multivariate Lasso model was developed to predict risk scores based on gene expression profiles. Results: Gene copy number variation analysis showed that among the 55 cases, 19 cases had MYCN amplification. There are slightly more responders to immunotherapy and DFMO among MYCN-amplified (MNA) patients (not statistically significant). Survival analysis showed that immunotherapy and DFMO treatment achieved similar survival rates for both MNA and non-amplified patients. 112 DEGs were identified between responders and non-responders, with 190 DEGs in the MNA group and 74 in the MYCN non-amplified (MNN) group. Key genes such as PDZRN4, MGDA2, LINC00632, and ENTPD3 were identified as significant for survival in MNA patients. The DFMO-treated cohort with MYCN amplification did not show a significant relationship with poor survival (p-value = 0.8). A multivariate CPH model subjected to Lasso penalization identified five genes that distinguished high-risk and low-risk patients with significant survival disparity (p-value < 0.001). Pathway analysis showed that the Hippo signaling pathway was suppressed in MNN responders. Ribosomal protein gene expression was enriched in responders overall and in MNN responders, but not in MNA responders. STRING analysis revealed highly connected networks in DEGs, with stem cell factor SOX2 being a central node in MNA cases, indicating its role in maintaining stemness and promoting tumor propagation. Conclusion: DFMO combined with immunotherapy shows promise as an effective targeted therapy for both MNA and MNN NB, equalizing survival rates between MNA and MNN patients. This treatment may particularly target stem cell populations in MNA cases. Further validation is required to confirm these findings and refine the associated risk prediction models. Citation Format: Anderson O. Cox, Abhinav Nagulapally, Deha Ay, Qianqian Song, Liang Liu, Hong-Gang Wang, Abigail Moore, Valerie I. Brown, Wei Zhang, Giselle L. Saulnier Sholler. Targeted therapy with DFMO and immunotherapy equalizes survival in MYCN-amplified neuroblastoma: insights from genomic and network analyses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2623.