Abstract PR004: Characterization of patient-specific CHEK2 genetic variants in high-risk neuroblastoma

Abstract

Neuroblastoma (NB) is the most common extra-cranial solid tumor in children and accounts for approximately 10% of pediatric cancer deaths. Next-generation sequencing studies of patients with high-risk NB identified multiple pathogenic/likely pathogenic (P/LP) germline and oncogenic somatic variants in the Checkpoint kinase 2 (CHEK2) gene; however, roles for specific CHEK2 variants in NB formation, progression, and response to frontline therapeutics remain poorly understood. CHEK2 is involved in DNA damage repair, cell cycle arrest, and apoptosis through activation of multiple downstream effector proteins. Loss-of-function mutations in CHEK2 are found in a range of human cancers; however, the risk posed depends on the specific genetic variant and tumor subtype. To better understand the roles of certain CHEK2 variants in NB formation, progression, and responses to therapy, we used CRISPR/Cas9 gene editing to model P/LP CHEK2 variants identified by the SickKids Cancer Sequencing program (KiCS) in a transgenic zebrafish model of MYCN-driven NB (Zhu et al. 2012). Through direct visualization of EGFP+ NB formation and progression, we assessed CHEK2 variant-specific effects on tumor incidence, growth, and metastasis in vivo. Patient-derived NB cell lines were used to assess the effects of CHEK2 loss on proliferation, gene expression, and chemotherapy resistance. In zebrafish, a precision model of inherited CHEK2(1100delC) displayed increased MYCN-driven tumor formation compared to MYCN-only controls (p=0.0006, log-rank test). RNA sequencing and differential gene expression of EGFP+ zebrafish NB tumor cells revealed upregulation of gene expression associated with cilia assembly and movement. CHEK2 knockdown in SH-EP, Kelly, and SK-N-AS cell lines increased cilia formation in vitro, as well as chemotherapy resistance in certain cell lines, an effect that required the cilia-specific regulator, IFT88. Altogether, our data supports roles for certain genetic variants in CHEK2 in NB, as well as potential mechanistic targets for high-risk or therapy-resistant NB. Through modeling NB progression in vivo in the context of patient-specific P/LP CHEK2 variants, our work provides preclinical information to inform diagnostics and potential therapeutic strategies for high-risk NB. Xueting (Ting) Xiong, Meagan Beffort, Lynn Kee, Alex Weiss, Sarah Cohen-Gogo, Anita Villani, Adam Shlien, Meredith S. Irwin, Madeline N. Hayes. Characterization of patient-specific CHEK2 genetic variants in high-risk neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Bridging Discovery and Clinical Impact in Pediatric Cancer; 2026 Sep 22-25; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(18_Suppl_1):Abstract nr PR004.