The insulin-like growth factor-1 receptor (IGF-1R) is a central component of 
lung cancer signal transduction pathways. A phase III study failed for 
carboplatin, paclitaxel, with or without figitumumab in first-line treating 
metastatic non-small cell lung cancer (NSCLC). There is an urgent need for a 
better understanding of signaling in IGF system. Insulin-like growth 
factor-binding proteins (IGFBPs) function as modulators for IGF signaling 
through sequestration of IGFs in serum and the extracellular fluid. IGFBPs can 
also act as transporters or modulators for IGF action and insulin action. IGFBPs 
have attracted increased attention for their lung cancer-related role in recent 
years. Recent studies have demonstrated the critical role of IGFBPs in risk 
assessment, early detection, prognosis evaluation, and drug resistance appraisal 
for lung cancer. These observations suggest a potential new approach to 
understand the pathogenesis of lung cancer, have important clinical 
implications, while additional investigations are necessary.