Association of IGFBP-6 Expression with Metabolic Syndrome and Adiponectin and IGF-IR Receptor Levels in Colorectal Cancer

Purpose:To assess IGFBP-6 expression in relation with the presence of the metabolic syndrome, adiponectin receptors (AdipoR1 and AdipoR2) and IGF-IR levels in colorectal adenocarcinoma cases. Materials and Methods: IGFBP-6 mRNA and protein levels were analyzed using real-time quantitative PCR and Western blotting in 46 patients. ELISA and flow cytometry were used for evaluation of AdipoR1, AdipoR2 and IGF-IR. Results: The results showed that IGFBP-6 mRNA expression and the IGFBP-6 content were higher in tumor tissue samples of colorectal cancer patients with tahtn without metabolic syndrome. In addition, the IGFBP-6 mRNA expression was associated with tumor invasion (tumor size) and the IGFBP-6 protein level was associated with nodal status. Positive correlations and positive nonlinear relations were found between the IGFBP-6 level and the AdipoR1 and AdipoR2 contents in colorectal cancer patients. Conclusions: The IGFBP-6 mRNA level and protein level were found to be associated with presence of metabolic syndrome. Positive correlations indicated probable cross-talk between the IGF-IR-mediated and adiponectin-mediated signaling pathways in colorectal carcinomas. IGFBP-6 may be considered as a potential biomarker associated with lymphogenous metastasis and the metabolic syndrome in colorectal cancer.