Altered expression of SIRT gene family in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) include a group of malignant neoplasms that arise from the upper aerodigestive tract and represent the seventh most common cause of cancer-related death. The overall 5-year survival rates have not significantly improved for decades in spite of the advances in the field of oncology and surgery, encouraging further research on factors that might modify disease prognosis. The silent information regulator (SIR) genes (Sirtuins) play key roles in cellular stress and are associated with aging-related diseases including cancer. Currently, seven human sirtuin (SIRT1-7) genes have been identified, but the roles of SIRT genes in HNSCC are still uncertain. Therefore, in this study, we used real-time quantitative reverse transcription-polymerase chain reaction to investigate the expressions of the seven SIRT genes in human HNSCC tissues to assess the changes in cancerous and noncancerous parts and the correlation with different tumor behaviors. Our results demonstrated that the expression levels of SIRT1, SIRT2, SIRT3, SIRT5, SIRT6, and SIRT7 were significantly downregulated in cancerous tissues compared with noncancerous tissues (all p<0.01). The expression levels of SIRT1, SIRT2, SIRT3, SIRT5, and SIRT7 showed downregulation in advanced stages in respect to early stages (p<0.05). These results indicate that the downregulation of SIRT genes expression may contribute to the development of cancer and trigger the neoplastic disease to more advanced stages. Our study indicates that SIRT genes expression could help in the diagnosis and represent a prognostic biomarker in HNSCC.