Lung cancer is one of the most frequent causes of cancer death in Western countries. Overall 5-year survival rate is lower than 15% mainly due to the late diagnosis of the disease. Primary prevention (reduction of tobacco consumption) and more effective methods for early detection are needed. Some studies have recently shown that low-dose spiral computed tomography (CT) is a useful technique to the detection of pulmonary malignant nodules in early stages. Studies are developing to evaluate its efficacy in series of high-risk patients. A new cytogenetic technique has been developed: the FICTION technique (Fluorescence Immunophenotyping and Interphase Cytogenetics as a Tool for the Investigation of Neoplasms). This technique allows the simultaneous study of immunophenotypic markers and genetic abnormalities present in tumour cells. The goal of our project is optimise this technique in sputum and bronchoalveolar lavage specimens from lung cancer patients. The overall goal of this project is evaluate the usefulness of this technique, together with the new radiological techniques, in early detection programs of lung cancer in high-risk patients. In the present study we review the cytogenetic studies on lung cancer carried out in the recent years. We also introduce the basic methodological aspects that will be developed in our project.