In KU539, the DCIS clone in no. 5 had two driver mutations in PIK3CA and CBFB in addition to a GATA3 mutation and der(1;16), although the invasive cancer clone (in no. 4) in the same clade had no additional driver alterations (Extended Data Fig. 5a). The gene discussed is PIK3CA; the disease is ductal breast carcinoma in situ.