Abstract: Objective: To study the value of the expression of Lunx mRNA in the peripheral blood in detecting the micrometastasis in patients with non-small cell lung cancer (NSCLC)and assessing the prognosis and efficacy of chemotherapy.Methods: Fluorescence quantitative polymerase chain reaction (PCR) was used to detect the expression of Lunx mRNA in the peripheral blood samples from 66 patients with NSCLC and 40 patients with benign pulmonary lesions.The NSCLC patients the cases were followed up for 1 to 40 months,and the relationship between the expression of Lunx and the survival rate of the patients were observed.The objective response of 50 NSCLC patients receiving chemotherapy was evaluated every two cycles.Results: The positive expression of Lunx mRNA was 57.6% in the peripheral blood of patients with NSCLC.The median of copy number was 48 copies/ml.Significant difference of the expression level of Lunx was found in different TNM stages of the lung cancer.No patients with benign pulmonary disease showed positive expression of Lunx mRNA.The overall survival rate in patients with positive expression of Lunx mRNA was obviously lower than that with negative expression (P<0.01).But the expression was not related to the efficacy of chemotherapy (P>0.05).Conclusions: The expression of Lunx mRNA in the peripheral blood has great predictive value for the prognosis of patients with NSCLC.