Therefore, our studies not only provide a view of the multiple levels at which HIPK2 might fine-tune the transcriptional activity of p53 in tumor cells subjected to genotoxic stress, including the novel acetylation/deacetylation balance and Sirt1 regulation, but also may be relevant for designing new strategies for treatment of tumors with non-functional wtp53 and/or HIPK2. Here, SIRT1 is linked to neoplasm.