The ER+ baseline tumour contained a CDH1 splice-site mutation in the founder clone, and subclonal missense mutations in FOXA1 and FOXQ1. The surgical tumour specifically lacked these mutations or indeed other SNVs or indels in genes strongly implicated in cancer, but had focal amplifications containing MYC, EGFR and CCND1 (Fig. 1b). Here, EGFR is linked to cancer.