CDKN1A and neoplasm: In HepG2 xenograft model, body weight gradually increased in the control group while kept relatively stable in CuPT-treated group (Figure 8a and b); tumor volume gradually decreased and the tumor weight was significantly reduced in the CuPT treatment group compared to the vehicle control (Figure 8c–e); the immunostaining results showed that the proteasome substrate levels such as total or K48-linked ubiquitinated and p21 proteins were significantly increased in the CuPT-treated tumor tissues (Figure 8f).