SIRT1, class III histone deacetylase, has been described to be up-regulated in various malignancies. However, the opposite results have been reported in other malignancies. Therefore, we investigated SIRT1 expression to clarify its biological behavior and identify its usefulness as a biomarker for head and neck squamous cell carcinoma (HNSCC).Study Design.
SIRT1 expression was assessed by immunohistochemistry (IHC) conducted using samples from 437 consecutive HNSCC patients. Acetylated histone status and p53 expression were also examined.Results and Conclusion.
IHC revealed 79.6% staining of SIRT1 in HNSCC, while almost all normal tissues showed positive staining. SIRT1 expression predominated in cases involving patients aged >65 years, lymph node negative, and early clinical stage cases. It was positively and statistically correlated with expression of acetylated histone H3K9 and H4K16, but not with p53. Multivariate analyses revealed that expression of SIRT1 was an independent and good indicator of prognosis.