Clinicopathologic Characteristics And Prognosis Of Patients With Lung Adenocarcinoma Harboring ALK Gene

Objective: To investigate the clinicopathologic characteristics and prognosis of patients with lung adenocarcinoma harboring anaplastic lymphoma kinase(ALK) gene.Methods: The expression of ALK gene was detected in 256 paraffin-embedded lung adenocarcinoma tissues using immunohistochemistry(IHC),and compare prognosis of patients between the four groups(3+,2+,1+,0). ALK gene expression in groups(3+,2+) was confirmed by quantitative rea-time-PCR(q PCR), 23 tissues were found ALK gene positive,197 tissues in IHC(0) group were defined as ALK gene negative. Differences of clinicopathologic characteristics and prognosis of patients were analyzed between ALK-positive group and ALK-negative group.Results:(1) ALK gene was expressed in the cytoplasm. The positive rate was 8.98% in 256 cases.The expression level of ALK in(< 60 years old) group was significantly higher than(> 60 years old) group(c2= 6.117, P< 0.05),and nonsmoking group higher than smoking group(c2 = 12.124, P< 0.05). Expression level of ALK showed no difference among genders(c2 = 2.950, P > 0.05) 、TNM stage(c2 = 3.563, P> 3.563) and lymph node metastasis(c2 = 0.737, P> 0.737).(2) There was no correlation between IHC classification and prognosis of lung adenocarcinoma patients(c2 =6.60,P>0.05).The three years survival rate between IHC(3+)group and IHC(2+)group, IHC(2+) group and IHC(1+) group, IHC(1+)group and IHC(0)group showed no statistical difference(c2 = 1.092, P> 0.05; c2 = 0.577,P> 0.05; c2 = 0.056, P> 0.05).(3) The three year survival rates were significantly lower in the positive group than in the negative group(43.5% vs71.6 %, c2 = 7.552, P< 0.05).The overall survival time was shorter in the ALK-positive group than in the ALK-negative group by Kaplan-Meier survival analysis,as well as median overall survival(33.5months vs 49.1months,P<0.05).Conclusion: The expression level of ALK gene in lung adenocarcinoma patients is much higher in young and no smoking patients. Expression of ALK gene is may be one of the independent prognostic factors for patients with lung adenocarcinoma.And examining expression of ALK gene in lung adenocarcinoma patients may has practical values in estimating the prognosis of patients and directing future treatment.