Introduction: Minimal systemic disease (MSD) means the presence of circulating or disseminated tumour cells in mesenchymal compartments of a patientts' body (lymphatic nodes, blood or bone marrow). The aim of our pilot study was to identify sensitive and specific markers for MSD detection in 50 lung cancer patients, who underwent curative surgery in the I. Department of Surgery, Faculty of Medicine and Dentistry, Palacky University and Faculty Hospital Olomouc in 2009 and 2010.
Material and methods: Absolute gene expression of carcinoembryonic antigen (CEA), epidermal growth factor receptor (EGFR1), lung-specific X protein (LUNX) and hepatocyte growth factor receptor (c-met) was determined in peripheral blood, bone marrow and pulmonary blood of 50 lung cancer patients using real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR).
Results: (1) The LUNX marker is specific and sensitive for MSD detection in lung cancer patients. (2) The CEA positivity for MSD in the bone marrow correlated significantly with histopathological grading (GI-GIII). (3) Higher expression of CEA and c-met was found in pulmonary blood of patients with hilar or mediastinal lymphadenopathy. (4) Higher expression of MSD markers (CEA in bone marrow, c-met in peripheral blood and LUNX in pulmonary blood) correlated with higher pTNM classification.
Conclusion: Minimal systemic disease detection in lung cancer patients is technically feasible using sufficiently sensitive and specific markers for RT-PCR. Minimal systemic disease detection can be used to guide further systemic treatment. This theory must be validated in a larger group of patients and correlated with clinical data, especially with survival data.