Local IGFBP-3 mRNA expression, apoptosis and risk of colorectal adenomas

Abstract

IGF binding protein-3 (IGFBP-3) regulates the bioavailability of insulin-like growth factors I and II, and has both anti-proliferative and pro-apoptotic properties. Elevated plasma IGFBP-3 has been associated with reduced risk of colorectal cancer (CRC), but the role of tissue IGFBP-3 is not well defined. We evaluated the association between tissue or plasma IGFBP-3 and risk of colorectal adenomas or low apoptosis. Subjects were consenting patients who underwent a clinically indicated colonoscopy at UNC Hospitals and provided information on diet and lifestyle. IGFBP-3 mRNA in normal colon was assessed by real time RT-PCR. Plasma IGFBP-3 was measured by ELISA and apoptosis was determined by morphology on H & E slides. Logistic regression was used to compute odds ratio (OR) and 95% confidence intervals. We observed a modest correlation between plasma IGFBP-3 and tissue IGFBP-3 expression (p = 0.007). There was no significant association between plasma IGFBP-3 and adenomas or apoptosis. Tissue IGFBP-3 mRNA expression was significantly lower in cases than controls. Subjects in the lowest three quartiles of tissue IGFBP-3 gene expression were more likely to have adenomas. Consistent with previous reports, low apoptosis was significantly associated with increased risk of adenomas (p = 0.003). Surprisingly, local IGFBP-3 mRNA expression was inversely associated with apoptosis. Low expression of IGFBP-3 mRNA in normal colonic mucosa predicts increased risk of adenomas. Our findings suggest that local IGFBP-3 in the colon may directly increase adenoma risk but IGFBP-3 may act through a pathway other than apoptosis to influence adenoma risk.

DOI: 10.1186/1471-2407-8-143

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Cite this paper

@article{Keku2007LocalIM, title={Local IGFBP-3 mRNA expression, apoptosis and risk of colorectal adenomas}, author={Temitope O. Keku and Robert S. Sandler and James G. Simmons and Joseph Galanko and John T. Woosley and Michelle Proffitt and Oluwaseun A Omofoye and Maya McDoom and Pauline Kay Lund}, journal={BMC Cancer}, year={2007}, volume={8}, pages={143 - 143} }