The presence of an ESR1 mutation in the plasma also showed a trend towards enrichment in patients with luminal A status determined by PAM50 algorithm22, as 41.4% of patients with PAM50 defined luminal A tumours had ESR1 mutations compared with 31.8% of patients with luminal B tumours (Table 1 and Supplementary Table 1). The gene discussed is ESR1; the disease is neoplasm.