Expression of insulin-like growth factor 1 and its receptors in colorectal cancer and their significances

Abstract

Objective To investigate the expression of insulin-like growth factor 1 (IGF-1), insulin growth factor receptor 1 (IGF-1R) and insulin growth factor receptor 2 (IGF-2R) in colorectal cancer, and their relationship with the relevant clinicopathological factors. Methods Immunohistochemical SP method was used to detect the expression of IGF-1, IGF-1R and IGF-2R in 154 cases of colorectal cancer tissues, 58 cases of benign disease tissues (colorectal adenoma, polyps) and 90 normal tissues. Results The positive rate of IGF-1 and IGF-1R expression in colorectal cancer tissues [93.5% (144/154), 70.1% (108/154)] was higher than that in benign diseases [51.7% (30/58), 51.7% (30/58)] and adjacent normal tissues [18.9% (17/90), 35.6% (32/90)] (P= 0.001). The positive expression rate of IGF-1 and IGF-1R in colorectal cancer tissue, benign disease tissue and adjacent normal tissues decreased gradually, and there was significant difference between any two groups (P 0.05). IGF-2R was significantly different between any two groups (P 0.05). IGF-1 was positively correlatedwith the body mass index (r= 0.169, P= 0.036). IGF-2R was negatively correlated with age (r=-0.196, P= 0.015), and positively correlated with TNM staging in patients with colorectal cancer (r= 0.227, P= 0.005). The expression of IGF-1 was positively correlated with IGF-1R (r= 0.281, P= 0.000 1). There was no significant correlation between IGF-1 and IGF-2R in cancer tissues (P > 0.05). Conclusion IGF-1 and IGF-1R may promote the occurrence of colorectal cancer, and IGF-2R may be associated with the progress of colorectal cancer, and obesity is a risk factor for incidence of colorectal cancer. Key words: Colorectal neoplasms; Insulin-like growth factor-1; Receptor, IGF type 1; Receptor, IGF type 2