TP53 and neoplasm: Apoptin, encoded by the VP3 gene of the chicken anemia virus (CAV), is a small tumor-selective apoptosis-inducing protein with a unique mechanism of action: it triggers apoptosis through a p53- and Bcl-2-independent but caspase-dependent pathway, allowing it to effectively kill tumor cells with p53 mutations or loss of function—frequent events in HCC—while sparing normal cells [10,11].