ESR1 and neoplasm: Although there was some difference in the overall distribution of size, stage and grade of tumours between the Nottingham and Edinburgh series, the distribution of the NPI+ Biological Classes (Luminal A, Luminal N, Luminal B, Basal p53 altered, Basal p53 normal, HER2+/ER+, HER2+/ER−) was similar.