In this study, we aimed to develop a real-time RT-PCR assay to investigate the expression of four epithelial or cancer-related mRNA markers, survivin, hTERT, CK-7 and TTF-1, in order to detect levels of CTCs in PB samples of advanced lung adenocarcinoma patients as well as from healthy controls. This evidence concerns the gene TTF1 and lung adenocarcinoma.