Abstract 5188: Integrated exome analysis in childhood hepatoblastoma: Biological approach for next clinical trial designs

Abstract Background: Hepatobastoma (HBL) accounts for more than 80% of childhood hepatic malignant tumors. The outcome of the HBL cases mainly depends on the biological characteristics and disease stagings, but the candidate genes correlated with HBL progression have not been identified. Sequence capture enrichment strategies and massively parallel next generation sequencing (NGS) were used for such gene discovery.Methods: Out of approximately 300 HBL case treated according to the JPLT (Japanese study group for Pediatric Liver Tumor)-2 protocol, 48 samples cases were analyzed by a method for whole-exome sequencing coupling Ilumina Nextera whole-exome capture to the Illumina DNA-sequencing platform. In these cases, 10 had lung metastatic cases and 13 of the remaining 38 cases had vascular invasion or multifocal lesions at admission. Consequently, 14 cases had a relapse and 10 cases died of disease. Using conventional technology, we investigated CNNB1 point-mutations and deletions in these cases.Results: Among these 48 HBL cases, mutation and deletion in CNNB1 exon 3 was identified in 40 cases, which had been already detected by conventional techniques. The remaining 8 cases showed the mutation of Wnt signal genes including AXIN1 and FAP genes. Among the cases with metastatic lesion and/or consequently dead cases, stemness-associated and cancer-associated genes showed homozygous deletion (e. g. CDKN2A), a homozygous inversion in the genes including NF1, and an unbalanced translocation. The response rates in the 35 cases that underwent neo-adjuvant chemotherapy revealed that existence of the mutations in several genes associated with proliferation was significantly correlated with chemo-resistance. Therefore, we are now constructing next clinical trial for HBL based on the whole-exome era.Conclusions: Whole-exome sequencing using NGS in hepatoblastoma revealed several candidates mutated or deleted genes except for CNNB1 in Wnt-signaling pathway. NGS can be also used in research and diagnostic settings to screen for mutations and deletion/insertion of the genes associated with malignant grade and chemo-resistance. Further NGS analysis provided important candidates of indicators for diagnostic and therapeutic targets for HBL clinical trials. Note: This abstract was not presented at the meeting. Citation Format: Eiso Hiyama, Sho Kurihara, Yoshiyuki Onitake, Nagisa Morihara, Kyoko Ikeda, Keiko Hiyama. Integrated exome analysis in childhood hepatoblastoma: Biological approach for next clinical trial designs. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5188. doi:10.1158/1538-7445.AM2014-5188