ESR1 and breast carcinoma: To analyze the function of Memo on ERα downstream of E2 and HRG we chose the ERα+ / HER2+ (non-overexpressing, luminal B-like) human breast cancer cell line T47D stably expressing a control, non-targeting (NT), short hairpin RNA (shRNA), or one expressing Memo shRNA (Sh5) (Figure 1A).