Our observation that intestinal SIRT1-deficiency decreases polyp load and increases apoptosis in the APC+/min model, and that pharmacological inhibition of SIRT1 in APC-mutated colon cancer cell lines leads to p53 hyeperacetylation, provide additional support for importance of such an autoregulatory loop in the intestinal tumorigenesis. The gene discussed is APC; the disease is malignant colon neoplasm.