The clonogenic survival assay showed that the survival rate of cells was significantly reduced after adding the inhibitor LY294002 (all P < .05, Figure 6D) compared with the ATF3 overexpression group, suggesting that the breast cancer radioresistance established by the ATF3 overexpression can be alleviated by inhibiting the PI3K/Akt signalling pathway. Here, AKT1 is linked to breast carcinoma.