Association between components of the insulin-like growth factor system and endometrial cancer risk

Objective: The insulin-like growth factor (IGF) system has been related to cell proliferation, obesity, diabetes, hyperinsulinemia and endometrial cancer risk. We used data from a case-control study conducted in Italy to provide additional information on the relation between the IGF system and endometrial cancer. Methods: A case-control study was conducted between 1999 and 2002 in Italy, including a total of 73 women with incident, histologically confirmed endometrial cancer and 108 controls admitted to the same hospital network for acute, nonneoplastic diseases. All subjects were interviewed using a validated questionnaire. Results: The odds ratios for endometrial cancer comparing the highest versus the lowest tertile of various IGF components were as follows: 0.5 [95% confidence interval (CI) 0.2-1.2] for free IGF-I, 1.1 (95% CI 0.5-2.6) for total IGF-I, 1.2 ( 95% CI 0.6-2.6) for total IGF-II, 2.4 (95% CI 1.0-5.9) for IGF binding protein (IGFBP)-1 and 0.8 (95% CI 0.4-2.0) for IGFBP-3. Further allowance for all IGF components in the model did not modify the results. The direct relation with IGFBP-1 was stronger and limited to heavier and older women. Conclusions: The present findings suggest a limited effect of the IGF system on endometrial cancer risk. Increasing IGFBP-1 levels seem to be associated with endometrial cancer risk in older women and in women with a higher body mass index.