In this study, we found that SIRT1 directly binds to and deacetylates FOXM1 (Figure 2), and participates in regulating FOXM1 acetylation status during cell cycle (Figure 1E) and FOXM1 transcriptional activities (Figure 4), indicating that SIRT1 acts as a tumor suppressor in regulating FOXM1 activity. The gene discussed is SIRT1; the disease is neoplasm.