In addition, IHC staining of Ki‐67, H2BK120ub and TFRC in frozen sections from all four groups indicated that USP22 knockout promoted H2BK120ub and TFRC levels in transplanted tumours, and inhibited hepatocellular carcinoma malignancy as indicated by Ki‐67 staining, especially after Sorafenib treatment (Figure 8G‒J). The gene discussed is TFRC; the disease is hepatocellular carcinoma.