Despite a close interplay of the involved pathways, there are increasing numbers of reports indicating that tamoxifen [160], epirubicin [161], doxorubicin [157,162], paclitaxel [163], and even the novel CDK4/6 inhibitor palbociclib [134,164] induced autophagic flux in parental and drug-resistant ER+ and TNBC cells. Knocking down key autophagy genes (ATG5, BECN1, or ATG7) in combination with TAM treatment resulted in decreased cell viability in MCF7 and T47D breast cancer cell lines. Here, BECN1 is linked to breast cancer.