Hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) analysis of tumor tissues indicated that bufalin reduced the expression levels of both proliferating-cell nuclear antigen (PCNA) and ATP1A1, as well as S5a and PSMB5, two proteasome subunits, identical as observed in the cell-based assay (Lan et al., 2018). Here, PCNA is linked to neoplasm.