ESR1 and breast carcinoma: As shown in Fig. 1A–C, the baseline level of HIF1α in untreated control MCF10A cells (40 ± 4.34 pg/ml), was much lower than that in both ER +ve (300 ± 32.03 pg/ml) or ER−ve (1000 ± 59.21 pg/ml) breast cancer cells.