AKT1 and breast cancer: Bortezomib, as a proteasome inhibitor, has an anti-tumor effect in HCC, HNSCC, leukemia, breast cancer, and colon cancer by inhibiting the CIP2A-PP2A-AKT signaling pathway (Chen et al., 2010; Lin et al., 2012; Tseng et al., 2012; Liu et al., 2013; Ding et al., 2014).