Molecular detection and prognostic value of epithelial markers mRNA expression in peripheral blood of advanced non-small cell lung cancer patients

BACKGROUND: Few studies, have evaluated the prognostic impact of the quantification of mRNA expression levels in advanced non-small cell lung cancer (NSCLC). OBJECTIVE: The aim of this work was to quantify mRNA expression levels in peripheral blood through three epithelial markers in patients with stages IIIB and IV in NSCLC. METHODS: Seventy advanced NSCLC patients and ten healthy controls were included. All patients received platinum-based chemotherapy in first line treatment. Peripheral blood was obtained of each participant and mRNA expression levels present in circulating cells were quantified by molecular techniques (RT-PCR) using three epithelial markers: cytokeratin (CK)-18, CK-19 and Carcinoembryonic-Antigen (CEA). The expression levels were quantified from a standard curve using the cDNA obtained from A549 cells. Registered in ClinicalTrials. gov (NCT01052818). RESULTS: We found a significant statistical correlation between levels of CK-18, CK-19 and CEA mRNA. mRNA expression levels were lower in patients who present three or less metastasis; higher CEA mRNA expression was associated a worse progression-free survival to platinum-based chemotherapy and overall survival. CONCLUSION: RNA expression of CEA by RT-PCR is useful as a prognostic marker in advanced NSCLC.