Abstract 4905: Comprehensive genomic analyses of oral squamous cell carcinoma tissues by semiconductor-based next-generation sequencing

Abstract

Abstract Somatic mutation analysis is standard of practice for human cancers in order to identify therapeutic sensitizing and resistance mutations. We performed comprehensive genomic analyses that use PCR target enrichment and next-generation sequencing on the Ion Torrent Personal Genome Machine (PGM). We first validated a multigene sequencing screen interrogating 2855 mutational hotspots in 50 cancer-related genes using the Ion Torrent AmpliSeq cancer panel v2. Ten nanogram of DNA was used as template to amplify 207 regions in oral squamous cell carcinoma (OSCC). Approximately 1000 average coverage was obtained with more than 90% of target bases having at least 100 sequence reads. We detected mutations of the TP53 gene in 96% (22 of 23) of OSCC cell lines. Of the 62 OSCC specimens, 42 presented at least one somatic mutation among the 50 investigated genes, and 21 of these showed multiple gene somatic mutations. The most frequent mutations were detected on TP53 (26 of 62; 41.9%). CDKN2A mutations were identified in 9 cases; STK11 mutations were observed in 8 cases; and PIK3CA were mutated 5 cases. In addition, we sequenced 409 cancer-related genes in matched tumor and normal DNA from OSCC patients using the Ion Ampliseq Comprehensive Cancer Panel. This panel targets all exons of 409 tumor suppressor genes and oncogenes frequently cited and frequently mutated (covered regions: 95.4% of total), and 15,992 amplicons amplify more than 1.2 megabases of target sequence. We piloted the use of this platform to identify somatic mutations in 37 OSCC specimens including formalin-fixed paraffin-embedded (FFPE) samples. We also detected copy number variations (CNVs) in which segments of the genome can be duplicated or deleted from sequencing data. This targeted next generation sequencing using low amounts of FFPE DNA is a valuable tool for high-throughput genetic testing in research and clinical settings. Citation Format: Takafumi Nakagaki, Yasushi Sasaki, Kenta Kobashi, Kousuke Takeda, Miyuki Tamura, Tomoko Ohashi, Kazuhiro Ogi, Masashi Idogawa, Hiroyoshi Hiratsuka, Takashi Tokino. Comprehensive genomic analyses of oral squamous cell carcinoma tissues by semiconductor-based next-generation sequencing. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4905. doi:10.1158/1538-7445.AM2015-4905