Objective: Pulmonary metastasis is a main cause of death for the patients with osteosarcoma (OS), although no specific genetic alteration associated with pulmonary metastasis has been reported. The objective of this study was to identify candidate somatic genetic alteration contributed to pulmonary metastasis in pediatric OS.

Methods: Five sample sets including the tissues taken from primary tumor (P), resected pulmonary metastatic tumor (M), and normal tissue (N) of the same pediatric OS patients were analyzed by whole exome sequencing with Ion Torrent Proton sequencer. 40ng of genomic DNAs extracted from each tissue were used for multiplex PCR amplification with Ion Ampliseq Exome Kit. Data analysis including alignment to the hg19 human reference genome and variant calling was done using the Torrent Suite Software. Obtained genomic data was validated by visualizing in Integrative Genomics Viewer or capillary sequencing. Candidate somatic genetic alterations were annotated by wANNOVAR database. Pathway analysis was performed using GeneMANIA.

Results: Mean read depths on the P, M, and N were 219, 212, and 109, respectively. We identified 1364 and 1311 candidate non-synonymous somatic single nucleotide variants (SNVs) among the P and M, respectively. After the validation and filtering, we detected 135 non-synonymous SNVs within the exon region in M. Among these, 32 SNVs were overlapped with those in P. Only 2 recurrent SNVs were identified within the whole SNVs. C:G>T:A transition mutations were frequently observed in both P and M, and the frequency were higher in M comparing to P. Pathway analysis showed a significant enrichment of the candidate SNVs in genes involved in extracellular matrix regulation (FDR;2.37E-03).

Conclusion: We have identified 137 SNVs associated with pulmonary metastasis from pediatric OS. Extracellular matrix-relating signature might contribute to the genesis of pulmonary metastasis.

Citation Format: Shintaro Iwata, Yasutoshi Tatsumi, Tsukasa Yonemoto, Hiroto Kamoda, Takeshi Ishii, Hiroki Nagase, Miki Ohira. Detection of somatic mutations associated with pulmonary metastasis of osteosarcoma by whole exome sequencing. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2426.