Plasma insulin-like growth factor 1, insulin-like growth factor binding protein 3, and risk of colorectal cancer: a prospective study in northern Sweden.
BACKGROUND
Insulin-like growth factor 1 (IGF-1) has antiapoptotic and mitogenic effects on various cell types, and raised IGF-1 levels are increasingly being implicated as potential risk factors for cancer.


OBJECTIVE
To examine the relationship between IGF-1 and its major plasma binding protein, IGF binding protein 3 (IGFBP-3), and the risk of colorectal cancer.


METHODS
We conducted a case-control study nested within the Northern Sweden Health and Disease Cohort. IGF-1 and IGFBP-3 were measured in prediagnostic plasma samples from 168 men and women who developed cancers of the colon (n=110) or rectum (n=58), and from 336 matched controls.


RESULTS
Conditional logistic regression analyses showed an increase in colon cancer risk with increasing levels of IGF-1 (odds ratios (ORs) 1.00, 1.89, 2.30, 2.66; p(trend)=0.03) and IGFBP-3 (ORs 1.00, 0.91, 1.80, 1.93; p(trend)=0.02). Rectal cancer risk was inversely related to levels of IGF-1 (ORs 1.00, 0.45, 0.33, 0.33; p(trend)=0.09) and IGFBP-3 (ORs 1.00, 0.75, 0.66, 0.49; p(trend)=0.21). Mutual adjustments between IGF-1 and IGFBP-3 did not materially alter these relationships.


CONCLUSIONS
These results support earlier findings of increased risk of colon cancer in subjects with elevated plasma IGF-1. Our results however do not support the hypothesis that the risk of rectal cancer could also be directly related to IGF-1 levels.
Palmqvist
R
R
Department of Medical Biosciences, Pathology, Umeå University, SE-901 87 Umeå, Sweden.
Hallmans
G
G
Rinaldi
S
S
Biessy
C
C
Stenling
R
R
Riboli
E
E
Kaaks
R
R
D000328:Adult; D000886:Anthropometry; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000097:blood*; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood*; D016017:Odds Ratio; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000097:blood*; D012307:Risk Factors
D018972:Insulin-Like Growth Factor Binding Protein 3; D009363:Neoplasm Proteins; D007334:Insulin-Like Growth Factor I