Angiosarcoma heterogeneity and potential therapeutic vulnerability to immune checkpoint blockade: insights from genomic sequencing

BACKGROUND: Angiosarcoma is an aggressive tumor. Recent case series describe exceptional responses to checkpoint blockade in this disease. METHODS: Herein, we explored the genomic correlates of 48 angiosarcomas from the Angiosarcoma Project (12,499 variants analyzed in 6603 genes; whole-exome sequencing) versus 10,106 pan-cancer tumors in The Cancer Genome Atlas including 235 sarcomas but no angiosarcoma. RESULTS: At the molecular level, angiosarcomas were heterogeneous. Those located in the face and scalp presented high tumor mutation burden, missense amino acid variations biased towards more hydrophobic (and therefore more immunogenic) peptides, and ultra-violet mutational signature. CONCLUSIONS: Angiosarcoma molecular features are similar to those observed in melanoma and other skin tumors and may explain comparable immunotherapy sensitivity of these tumor types.