ESR1 and breast carcinoma: Similar to reports regarding genetic changes that promote more aggressive ER+ breast cancer phenotypes (46–49), we found that the differential gene expression pattern in Luminal A DAB2IP-low tumors correlates closely with genes expressed in Luminal B and HER2 tumors, irrespective of their DAB2IP status (Figure 2, A and B, and Supplemental Figure 1B).