title: Plasma insulin-like growth factor I is inversely associated with colorectal adenoma recurrence: a novel hypothesis.
abstract: The insulin-like growth factor I (IGF-I) axis has been proposed to be a significant factor in the development of certain cancers, including colorectal. However, results from epidemiologic studies suggest modest effects on colorectal cancer risk. Using cross-sectional and prospective study designs within the same cohort of men who had at least one adenoma at baseline, we investigated whether plasma IGF-I, IGF-I binding protein 1, and IGF-I binding protein 3 were associated with colorectal adenoma characteristics at baseline and whether their levels were related to odds for adenoma recurrence. Plasma levels of each marker were measured at baseline in 299 male participants in the Wheat Bran Fiber Trial, who were followed prospectively for recurrence of their adenomatous lesions. In cross-sectional analyses, plasma IGF-I was significantly positively associated with the presence of adenomas with any villous features (P = 0.04). In contrast, IGF-I levels were inversely associated with odds of colorectal adenoma recurrence, with adjusted odds ratios (95% confidence interval) of 0.55 (0.29-1.01) and 0.49 (0.26-0.91) for the second and third tertiles of IGF-I, respectively, compared with the first tertile (P(trend) = 0.02). The inverse association was stronger for advanced adenoma recurrence (P(trend) = 0.02) than for nonadvanced recurrence (P(trend) = 0.10). These results suggest that, once an adenoma is removed, higher IGF-I levels reduce the odds of the formation of new lesions in the colorectum.
authors.affiliation: Arizona Cancer Center, Arizona College of Public Health , University of Arizona P.O. Box 245024, Tucson, AZ 85724-5024, USA. jacobse@u.arizona.edu
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Jacobs
authors.forename: María Elena
authors.initials: ME
authors.lastname: Martínez
authors.forename: David S
authors.initials: DS
authors.lastname: Alberts
authors.forename: Erin L
authors.initials: EL
authors.lastname: Ashbeck
authors.forename: Susan M
authors.initials: SM
authors.lastname: Gapstur
authors.forename: Peter
authors.initials: P
authors.lastname: Lance
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Thompson
mesh_terms: D000236:Adenoma / Q000097:blood*; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000097:blood*; D003430:Cross-Sectional Studies; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood*; D011446:Prospective Studies
chemical_list: D014408:Biomarkers, Tumor; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I