Since doxorubicin exerts an anti‐cancer effect by binding to TOP2A and impeding DNA replication, we first verified the effect of doxorubicin on the expression of TOP2A and UBE2C.[33] As shown in Figure 3A and Figure S5A (Supporting Information), doxorubicin significantly inhibited the expression of TOP2A but had little effect on the expression of UBE2C in breast cancer cells. This evidence concerns the gene TOP2A and breast cancer.