Notably, the fraction of partially or ambiguously mapped breakends did not vary substantially across cancer types (Extended Data Fig. 5d; range of 5–33%) or established cancer drivers (Extended Data Fig. 5e; range of 0–38%), although we observed tumor types (for example, acute myeloid leukemia) and cancer genes (SMARCB1, TSC2 and FGFR3) with higher (>25%) fractional burdens. This evidence concerns the gene SMARCB1 and neoplasm.