Molecular diagnosis of lung cancer: an overview of recent developments.

Health surveillance of workers occupationally exposed to lung carcinogens calls for screening procedures which may not be fully justified, owing to current uncertainties about the outcome of early detection. Indeed, bias-free designs are difficult to set up, and the effects of lead time, length and screening biases can all result in an overestimation of the benefits of screenings, which certainly increase survival, but without any actual reduction of mortality. A major issue with modern imaging techniques is the very high incidence of discovery of lung nodules, usually false positive, but still calling for additional and sometimes painful examinations. Currently, the differential diagnosis is mainly based on additional imaging approaches, particularly positron emission tomography, which is very expensive and also shows limitations in terms of sensitivity and specificity. Therefore, purely morphological criteria seem to be insufficient to distinguish lung cancer at early stages from benign nodules with sufficient confidence. A molecular approach to the diagnosis of lung cancer through biomarkers measured by non-invasive means could greatly improve the specificity of imaging procedures. Extremely sensitive mass spectrometric techniques and polymerase chain reaction-based methods are available to detect, in accessible media, molecular alterations which characterise lung cancer at an early stage, thereby reducing the rate of false positives. The lessons learnt from decades of screening programmes based on imaging and the future prospects possibly enhanced by using biomarkers are briefly discussed in this overview. (www.actabiomedica.it)