Not only serum tumor markers, such as carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC) and carbohydrate antigen (CA) 125, but also serum growth factors have been examined to evaluate tumor stages and to predict the recurrence and metastasis in patients with non-small cell lung cancer (NSCLC) (1-5). In recent years, the analysis of the genome and proteome has advanced remarkably. An array of molecular genetic tumor markers (MGTMs) have been identified based on the biological characterization of tumors, such as tumor development, growth, invasion and metastasis. Molecular genetic tumor marker research has also entered a new era, since comprehensive gene profile analysis using cDNA microarrays and comprehensive protein expression analysis using proteomics technology have been developed. On the other hand, the frequency of lung cancer patients with which various tumor markers are associated is increasing in Japan (6-8). This paper reviews MGTMs characteristic of lung cancer and clarifies the clinical usefulness and applications of MGTM for cancer treatment.