Study On The Expressions Of Livin And Smac Protiens In Non-small Cell Lung Cancer And Their Clinical Significance

ObjectiveToday lung cancer is the leading cause of cancer-related death world-wide. Recent studies have demonstrated that many apoptosis-related genes took part in the occurence and progression of lung cancer.Livin is a new member of the IAPs family (inhibitor of apoptosis proteins) which is highly expressed in the most malignancy, and it has been reported to play an important role in the inhibition of cell apoptosis. Smac(second mitochondrial activator of Caspase) is a newly found protein in mitochondrial membrane space.Study showed that Smac promoted apoptosis of cells by removing the inhibition of IAPs on caspase. In this study, we evaluate the Livin and Smac expressions by immunohistochemical technique, and discusse their roles in the occurrence,progression and prognosis of NSCLC.MethodsThe expressions of Livin and Smac proteins were detected in 89 NSCLC tissue samples and 25 normal lung tissue samples by immunohistochemical technique.ResultsThe positive expression rates of Livin and Smac proteins stain in NSCLC tissues were 53.9%(48/89),58.4%(52/89) respectively,which were higher than that in normal lung tissues, x₁²=16.723, x₂²=16.848,P =0.000. Livin protein expression correlated with Smac protein significantly, x²=18.451,P =0.000,r=0.455. Among all tumors, the expressive level of Livin protein was closely related to the lymph node metastasis(x²=19.433, P=0.000), TNM stages (x²=17.161, P=0.000)and histological types (x²=7.772, P=0.021), but not to sex(x²=1.590, P=0.207), age(x²=0.077, P=0.781), differentiation grades(x²=0.257, P=0.612),etc. The expressive level of Smac protein was closely related to the lymph node metastasis (x²=7.748, P=0.005), TNM stages (x²=7.064, P=0.008), but not to sex (x²=0.076, P=0.783), age(x²=1.124, P=0.289), histological types(x²=3.336,P=0.189),etc. Kaplan-Meier analysis revealed a significant impact on survival by Livin protein in NSCLC(x²=7.407,P=0.006), but not by Smac protein, (x²=0.945,P=0.331). Cox regression indicated that only lymph node metastasis,TNM stages,N stages,T stages were independent factors affecting the prognosis of NSCLC.ConclusionsOverexpression of Livin protein was closely related to the occurrence and progression of NSCLC. Moreover, it might bring bad affection to NSCLC patients' prognosis.Although the overexpression of Smac protein affected the occurrence and progression of NSCLC, it had no relationship with the prognosis. Livin protein may be helpful to evaluate the progression of NSCLC, and to predict the prognosis.