Table S1. Demographic and pathological features of human patients with angiosarcoma Table S2. Demographic and pathological features of dogs with HSA Table S3. Primary antibodies for immunohistochemical evaluation Table S4. Gene ontology and biological functions of fusion partner genes in human angiosarcomas Table S5. Gene ontology and biological functions of fusion partner genes in canine HSAs Table S6. Detection of fusion genes in canine HSAs by RT-PCR Table S7. Biological functions associated with 490 upregulated genes in human angiosarcomas Table S8. Association of frequency between fusion genes, TP53 and PIK3CA mutations Table S9. Association of fusion genes with dog signalment and tumor histology Table S10. Association of frequency between fusion genes, TP53 and PIK3CA mutations Table S11. 41 differentially expressed genes in PF (n = 4) compared to P (n = 9) group Table S12. 212 differentially expressed genes in PF (n = 4) compared to PK (n = 6) group Table S13. 377 differentially expressed genes in PF (n = 4) compared to PFK (n = 4) group Table S14. Immunohistochemical features of human angiosarcomas Table S15. Immunohistochemical features of canine HSAs
Funding
NCI
AKC Canine Health Foundation
National Canine Cancer Foundation
Morris Animal Foundation
NIH
Masonic Cancer Center, University of Minnesota
ARTICLE ABSTRACT
Sporadic angiosarcomas are aggressive vascular sarcomas whose rarity and genomic complexity present significant obstacles in deciphering the pathogenic significance of individual genetic alterations. Numerous fusion genes have been identified across multiple types of cancers, but their existence and significance remain unclear in sporadic angiosarcomas. In this study, we leveraged RNA-sequencing data from 13 human angiosarcomas and 76 spontaneous canine hemangiosarcomas to identify fusion genes associated with spontaneous vascular malignancies. Ten novel protein-coding fusion genes, including TEX2-PECAM1 and ATP8A2-FLT1, were identified in seven of the 13 human tumors, with two tumors showing mutations of TP53. HRAS and NRAS mutations were found in angiosarcomas without fusions or TP53 mutations. We found 15 novel protein-coding fusion genes including MYO16-PTK2, GABRA3-FLT1, and AKT3-XPNPEP1 in 11 of the 76 canine hemangiosarcomas; these fusion genes were seen exclusively in tumors of the angiogenic molecular subtype that contained recurrent mutations in TP53, PIK3CA, PIK3R1, and NRAS. In particular, fusion genes and mutations of TP53 cooccurred in tumors with higher frequency than expected by random chance, and they enriched gene signatures predicting activation of angiogenic pathways. Comparative transcriptomic analysis of human angiosarcomas and canine hemangiosarcomas identified shared molecular signatures associated with activation of PI3K/AKT/mTOR pathways. Our data suggest that genome instability induced by TP53 mutations might create a predisposition for fusion events that may contribute to tumor progression by promoting selection and/or enhancing fitness through activation of convergent angiogenic pathways in this vascular malignancy.
This study shows that, while drive events of malignant vasoformative tumors of humans and dogs include diverse mutations and stochastic rearrangements that create novel fusion genes, convergent transcriptional programs govern the highly conserved morphologic organization and biological behavior of these tumors in both species.
