Using an analysis of whole-exome sequencing from 31 treatment naive osteosarcoma tumour samples, Kovac et al. identified large-scale genome instability signatures characteristic of BRCA1/2-deficient tumours and recurrent mutations in tumour suppressor genes associated with homologous recombination and related DNA repair processes, including FANCA BRCA2 and ATM5. Here, FANCA is linked to neoplasm.