RESUMO
BACKGROUND: IGFBP-3 inhibits the mitogenic and anti-apoptotic activity of IGF by blocking the binding of IGF to its receptor. However, under certain circumstances, IGFBP- 3 can enhance the activity of IGF by protecting IGF from its degradation. More than half of the inter- individual variations in IGFBP-3 levels are known to be genetically determined by the polymorphism at -202 locus of IGFBP-3 gene. METHOD: We attempted to ascertain whether A-202C poly?morphic variation of IGFBP-3 gene constitutes a risk factor for non-small cell lung cancer (NSCLC), using PCR-restriction fragment length polymorphism (RFLP). Our study included 104 NSCLC patients and 104 age-, gender-, and smoking status-matched control subjects. RESULT: In the 104 NSCLC subjects, the genotypic freque?ncies at the -202 site were as follows: AA = 67 (64.4%), AC = 35 (33.7%), and CC = 2 (1.9%). We did detect significant differences in the genotypic distribution between the NSCLC and the control subjects (pAC>CC). Using CC genotype as a reference, the odds ratio (OR) for the subjects with AC genotype was 2.60 (95% CI: 0.89 - 8.60), and the OR associated with AA genotype was 5.89 (95% CI: 1.92 - 21.16). CONCLUSION: These results indicate that the dysregulation of IGF axis should now be considered as another important risk factor for NSCLC, and a potential target for novel antineoplastic therapies and/or preventative strategies in high-risk groups.