Background: Although multifocal neuroblastoma (NBL) is rare, its susceptibility is due to germline aberration and this predisposition gene may also be involved in sporadic neuroblastoma tumorigenesis. Sequence capture enrichment strategies and massively parallel next generation sequencing (NGS) were used for gene discovery because of their alterations. Methods: Out of approximately 500 NBL samples, 10 samples derived from 5 multifocal neuroblastoma cases were analyzed by a method for whole-exome sequencing coupling Agilent whole-exome capture to the Illumina DNA-sequencing platform. Using this technology, we investigated consistent point-mutations and insertions-deletions in these cases. Then, we analyzed the expression levels of these candidate genes in 298 sporadic NBL samples. Results: Among these 5 cases, one case showed ALK mutation in both of his multifocal tumors and germline mutation of ALK exon 23 (F1174L) was identified. The remaining 4 cases showed 57 candidate loci with consistent point-mutations and insertions-deletions including NBPF family genes and cell division cycle protein (CDC) genes. The expression levels of these candidate genes revealed that two genes were significantly decreased in these multifocal NBL tumors, except for one ALK mutated case. Then, we examined the expression levels of these two genes in sporadic NBL tumors. The expression levels of these candidate genes were significantly low in 34 and 59 NBL tumors, respectively but the low expression of both genes were detected in only two NBL tumors.Conclusions: Whole-exome sequencing using NGS in multifocal neuroblastoma revealed several candidate germline-mutated genes including ALK in such NBL-susceptibility cases. The expression levels of these genes also indicated that heterogeneous subtypes exist in sporadic NBLs. NGS can be used in research and diagnostic settings to screen for mutations and deletion/insertion in number of loci in genetically heterogeneous neuroblastoma. Further NGS analysis provided important candidates of indicators for diagnostic and therapeutic targets for NBLs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2502. doi:1538-7445.AM2012-2502