The aim of this study is to better understand the mechanism of lung cancer metastasis and to find new biomarkers for early diagnosis and new target for therapy by conducting comparative proteomics between the human high-metastatic large cell lung cancer cell lines (L9981) and L9981-nm23-H1 (constructed with transfecting nm23-H1 gene into the L9981 cell line). The gene discussed is NME1; the disease is lung large cell carcinoma.