ESR1 and cancer: BAG3 has previously been shown to modulate selective autophagy, proteotoxicity, resistance to stress and cancer-related signaling networks and we have shown that BAG3 expression is upregulated in SK-ERα cells.2, 17, 21, 47 Knockdown of BAG3 was accompanied by reduced levels of LC3-II after lysosomal inhibition in ERα-positive cells and to a lesser extend in SK-01 cells, demonstrating that BAG3 downregulation significantly impairs autophagic flux (Figures 6a–c).