Potential molecular approaches for the early diagnosis of lung cancer (Review)

Lung cancer is the leading cause of mortality from cancer among men and women worldwide. More individuals die each year of lung cancer than of colon, breast and prostate cancer combined. Despite new diagnostic techniques, the overall 5-year survival rate remains at approximately 15% and the majority of patients still present with advanced disease. Therefore, lung cancer is the most lethal cancer at present. Diagnosing and treating cancer at its early stages, ideally during the precancerous stages, could increase the 5-year survival rate by 3-4-fold, with the possibility of cure. To date, no screening method has been shown to decrease the disease-specific mortality rate. This review describes issues related to early lung cancer screening and their rationale, the management of primary cancers detected by screening and the different approaches that have been tested for cancer screening; these include imaging techniques, bronchoscopies and molecular screening, such as analysis of epigenomics using different noninvasive or invasive sources, such as blood, sputum, bronchoscopic samples and exhaled breath.