No association of insulin-like growth factor gene polymorphisms with survival in patients with colorectal cancer

Purpose: Insulin-like growth factors (IGF) regulate a wide range of biological functions including cell proliferation, differentiation, and apoptosis through paracrine and autocrine mechanisms. Accordingly, the present study analyzed polymorphisms of IGF genes and their impact on the prognosis for patients with colorectal cancer. Materials and Methods: Four hundred and two consecutive patients with curatively resected colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from fresh colorectal tissue and 8 polymorphisms of IGF genes determined using a real-time polymerase chain reaction genotyping assay. Results: Pathologic stages after surgery were as follows: stage 0/I (n=85, 21.1%), stage II (n=147, 36.6%), stage III (n=145, 36.1%), and stage IV (n=25, 6.2%). Multivariate survival analysis including stage, age, site of disease, and carcinoembryonic antigen level showed that the progressionfree survival for patients with the IGF2 +1280 GG genotype was slightly better than for the patients with the combined IGF2 +1280 AA and AG genotype (p=0.056), although there was no significant difference in the overall survival. However, the other polymorphisms were not associated with survival. Conclusion: None of the 8 IGF1 or IGF2 gene polymorphisms investigated in this study were found to be independent prognostic markers for Korean patients with surgically resected colorectal cancer.