Elevated C-peptide and insulin predict increased risk of colorectal adenomas in normal mucosa
Menée sur 190 patients présentant un ou plusieurs polypes adénomateux et sur 488 témoins, cette étude montre qu'un niveau sanguin élevé de peptide C et d'insuline est associé à un risque accru d'adénomes colorectaux
BACKGROUND:Lower concentrations of the insulin--like growth factor binding protein-1 (IGFBP-1) and elevated concentrations of insulin or C-peptide have been associated with an increase in colorectal cancer risk (CRC). However few studies have evaluated IGFBP-1 and C-peptide in relation to adenomatous polyps, the only known precursor for CRC.METHODS:Between November 2001 and December 2002, we examined associations between circulating concentrations of insulin, C-peptide, IGFBP-1 and apoptosis among 190 individuals with one or more adenomatous polyps and 488 with no adenomatous polyps using logistic regression models.RESULTS:Individuals with the highest concentrations of C-peptide were more likely to have adenomas (OR = 2.2, 95 % CI 1.4-4.0) than those with the lowest concentrations; associations that appeared to be stronger in men (OR = 4.4, 95 % CI 1.7-10.9) than women. Individuals with high insulin concentrations also had a higher risk of adenomas (OR = 3.5, 95 % CI 1.7-7.4), whereas higher levels of IGFBP-1 were associated with a reduced risk of adenomas in men only (OR = 0.3, 95 % CI 0.1-0.7). Overweight and obese individuals with higher C-peptide levels (>1st Q) were at increased risk for lower apoptosis index (OR = 2.5, 95 % CI 0.9-7.1), an association that remained strong in overweight and obese men (OR = 6.3, 95 % CI 1.0-36.7). Higher levels of IGFBP-1 in overweight and obese individuals were associated with a reduced risk of low apoptosis (OR = 0.3, 95 % CI 0.1-1.0).CONCLUSIONS:Associations between these peptides and the apoptosis index in overweight and obese individuals, suggest that the mechanism by which C-peptide could induce adenomas may include its anti-apoptotic properties. This study suggests that hyperinsulinemia and IGF hormones predict adenoma risk, and that outcomes associated with colorectal carcinogenesis maybe modified by gender.
BMC Cancer , article en libre accès, 2011