Usefullness of Serum Insulin-Like Growth Factor (IGF-1) and Insulin-Like Growth Factor Binding Protein-3 (IGFBP-3) for Colorectal Cancer Diagnosis

Insulin-like growth factor (IGF-1) is a potent mitogen and an anti-apoptotic agent which is regulated by insulin-like growth factor binding protein-3 (IGFBP-3). IGFBP-3 carries IGF-1 through the bloodstream to the target tissues and protects it from proteolytic degradation. IGFBP-3 reduces tumorigenic potential of colon cancer cells in vitro. IGFBP3 may inhibit target cells directly. In the present study, we assessed whether serum levels of IGF-I and IGFBP-3 could be used as tumor markers in patients with colorectal cancers and evaluated its relationship with known tumor markers, carcinoembryogenic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). Our study enrolled 40 patients diagnosed with colorectal cancer histopathologically and 40 completely healthy, agematched subjects (control group). Serum IGF-I levels were found significantly higher in patients with colorectal cancers compared to control group (p< 0.01). Serum IGFBP-3 levels were significantly lower in patients with colorectal cancers compared to control group (p< 0.05). The observed increase in CEA and CA19-9 levels in the same subjects were found statistically significantly higher compared to control group (p< 0.05). However, no significant association could be found between change in IGF-1 and IGFBP-3 levels and CEA or CA 19-9. Increased serum levels of IGFI might be considered as a significant predictor of tumor presence in patients with suspected colorectal cancer. Agents that could increase IGFBP-3 levels might be promising for the treatment of colorectal cancers.