Late-breaking abstract: Decreased sirtuin expression in squamous cell carcinoma compared to adenocarcinoma

Background. Sirtuin 1 (SIRT-1) is as an NAD+-dependent histone deacetylase. SIRT-1 has been shown to control cell cycle, proliferation and senescence, however the role of SIRT-1 in carcinogenesis is controversial. The aim of our study was to compare the SIRT-1 expression in lung squamous cell carcinoma and adenocarcinoma. Methods. 98 patients with lung nonsmall cell lung carcinoma were enrolled in the study. The control group consisted of 15 autopsy cases. The lung function testing was performed within one week before lung surgery. The SIRT-1 expression in lung cancer, peritumoral tissue and control group tissue was analyzed by immunohistochemistry and western blotting. Results. Obtained results showed increased SIRT-1 expression in lung nonsmall cell carcinomas compared to control group (146 ± 112 vs. 3 ± 1 cells/mm2; p=0.007). Furthermore, the SIRT-1 expression was upregulated in peritumoral tissue compared to control group (57± 31 vs. 3 ± 1 cells/mm2; p=0.001). In addition, the SIRT-1 expression was higher in squamous cell carcinoma compared to adenocarcinoma (204 ± 143 vs. 95 ± 49 cells/mm2; p=0.04). Furthemore, in patients comorbid with COPD and lung cancer, the SIRT-1 expression tended to be decreased compared to cancer patients without COPD. The positive correlation between disease stage and SIRT-1 expression was observed. Conclusion. Lung cancer is characterized by upregulated SIRT-1 expression, which is significantly increased in squamous cell carcinoma compared to adenocarcinoma and it correlates with disease stage.