MKI67 and persistent truncus arteriosus: The cellular expressions of Ki67+, PCNA+ and BrdU+ cells, three indicators of cell proliferation, were significantly higher in group 2 than in groups 1 and 3, and significantly higher in group 3 than in group 1, suggesting that PrPC essentially participated in regulating the cell proliferation after myocardial damage in the setting of TAC-induced TCM (Figure 7).