Analysis of insulin like growth factor 1 and insulin like growth factor binding protein 3 levels in bronchoalveolar lavage fluid and serum of patients with lung cancer

Objective: Insulin like growth factor 1 (IGF-1) is recognized as a potent mitogen for many cancer cell lines and there is good evidence that lung cancer cells produce both IGF-1 and insulin like growth factor binding protein 3 (IGFBP-3). The aim of this study was to investigate the clinical significance of IGF-1 and IGFBP-3 levels in serum and in bronchoalveolar lavage (BAL) fluid by comparing lung cancer patients with healthy controls. Methods: BAL fluid and serum samples were obtained from 24 lung cancer patients and 12 healthy controls, and were analyzed for IGF-1 and IGFBP-3 levels by a two site immunoradiometric assay. The recovered BAL fluid was standardized by albumin to remove the variable of dilution and the data was expressed in epithelial lining fluid (ELF). Results: Serum IGF-1 and IGFBP-3 levels were lower in lung cancer patients, but the difference between the groups did not reach a statistical significance. IGF-1/IGFBP-3 ratio in ELF was significantly lower in lung cancer patients (P = 0.035). Mean IGF-1 level in ELF was determined to be significantly lower in patients with distant metastasis (P = 0.04). Serum IGF-1/IGFBP-3 ratio was found to be significantly lower in patients with distant (P = 0.04) and nodal metastasis (P = 0.03). Tumor stage was negatively correlated with IGF-1 level in ELF (P = 0.05, r = -0.4) and serum IGF-1/IGFBP-3 ratio (P = 0.04, r = -0.4. Conclusion: IGF-1 and IGFBP-3 levels both in serum and ELF might serve a clinical significance in patients with lung cancer. However, further studies comprising more cases are needed to investigate the cIinical significance of IGF-1 and IGFBP-3 in lung cancer.