autophagy-related protein 12 (ATG12) was a downstream protein that Ambra1 regulated EPI-induced autophagy. Therefore, Ambra1 plays an important role in regulating the sensitivity of breast cancer cells to EPI. And the regulatory effect of Ambra1 on EPI sensitivity is achieved through the regulation of autophagy by targeting ATG12. ATG12 is a novel targeting protein of Ambra1 in regulating EPI-induced autophagy. The important role of Ambra1 in modulating the sensitivity of breast cancer cells to EPI is confirmed in vivo. The autophagic ubiquitin-like protein (ublp) autophagy-related (ATG)12 is a component of the ATG12 approximately ATG5-ATG16L1 E3 complex that promotes lipid conjugation of members of the LC3 ublp family.