To our surprise, significant high-level focal amplifications of all three MYC family genes (MYC, MYCL1 and MYCN) were frequently identified as subclonal events private to one tumour site sampled (56%, n = 9 of 16 cases), occurring either before (n = 3) or after therapy (n = 6), whereas patient-matched spatially or temporally distinct tumours lacked the amplification event (Fig. 4c,d and Extended Data Figs. 4c and 5e,f). The gene discussed is MYCN; the disease is neoplasm.