Screening of Mutations in the ras Family of Oncogenes by Polymerase Chain Reaction-Based Ligase Chain Reaction

Lung cancer is the most common fatal type of cancer in the developed world. The overwhelming majority of cases of lung cancer are caused by tobacco products (1) , and even with the best therapeutic approaches, less than 15% of diagnosed cases survive 5 years (2) . It has been noted that even after smoking cessation, the risk of lung cancer remains elevated for over 15 years (3) . This observation clearly indicates that lung cancer has a protracted course developing over a 10-20-yr period, from the moment in which an epithelial cell becomes initiated by chronic exposure to chemical insults until a clinically evident cancer is detected. The long latency period generated by this biology provides an important window of opportunity to find transformed precancerous cells in high-risk populations and intervene in a timely manner.