Abstract： Objective To evaluate the sensitivity, specificity and clinical significance of Lunx mRNA in surveying micrometastasis by sampling peripheral blood of lung cancer patients, studying the early diagnosis of lung cancer metastasis. Methods From March 2004 to February 2005，Reverse transcriptionpolymerase chain reaction(RT-PCR) was used to detect Lunx mRNA of peripheral blood of 60 lung cancer patients（lung ancer group）. Peripheral blood of 20 patients with pulmonary benign lesions (pulmonary benign lesions group) and 10 normal healthy volunteers (control group) were used as control. Results (1) In the lung cancer group, Lunx mRNA were expressed positive in 28(46.7％) patients. All the pulmonary benign lesions group (0/20) and the control group (0/10) were expressed negative. (2) One of the 12 stage I patients with lung cancer (8.3％) was positive for Lunx mRNA, 5 of the 15 stage Ⅱ patients (33.3%) were positive, 22 of the 33 stage Ⅲ patients (66.7%) were positive. Comparing the positive rate of these groups, there was no statistically difference between stage Ⅰ and stage Ⅱ, but the difference between stage Ⅰ+ stage Ⅱ and stage Ⅲ significant (χ2=15.88, P=0.000). (3) In 38 adenocarcinoma, 17 were positive for Lunx mRNA. In 14 squamous carcinoma, 7 were positive. All the 3 adenosquamous carcinoma expressed positive. 1 of 3 small cell lung cancer was positive, 1 large cell carcinoma and 1 carcinoma sarcomatodes expressed negative. Comparing the positive rate of these groups, there was no statistically difference among them. (4) By followup till March 2005, 10 lung cancer patients were found metastasis. Among them, 9 were positive for Lunx mRNA expression, and 1 was negative. Conclusion Lunx mRNA has high sensitivity and specificity in surveying micrometastasis by ampling peripheral blood. It would likely to be an proper gene for the detection of micrometastasis in lung cancer patients.