Of note, the luminal-like subgroup was enriched for the ‘group 2 set’ of genes associated with acquired endocrine therapy resistance in breast tumors that express ESR1 and ERBB2 (Figure 3D) (p < 10−6, FDR = 0.05), as reported by Creighton et al. [14]. Here, ESR1 is linked to breast neoplasm.