ESR1 and breast carcinoma: In this study, we investigated the effects of everolimus, as a single agent, or in combination with 4-hydroxy tamoxifen (4-OHT) or chloroquine on cell proliferation, anchorage-independent growth, PI3K/Akt/mTOR signaling, ER expression and transcriptional activity, LC3 turnover, and autophagosome induction in AI-sensitive MCF-7 and AI-resistant MCF-7:5C and MCF-7:2A breast cancer cells.