Furthermore, histological analyses with hematoxylin and eosin (H&E) staining, nuclear-associated antigen (Ki67) and terminal deoxynucleotidyl transferased dUTP nick end labeling (TUNEL) revealed that the mice receiving P4 treatment showed most severe cell remission and necrosis, the lowest activity of cell proliferation and the highest percentages of apoptotic tumor cells (Fig. 6e). The gene discussed is MKI67; the disease is neoplasm.