IGF-I, testosterone and breast cancer risk

✍ Scribed by Runhua Shi; Herbert Yu; Jerry W. McLarty; Jonathan Glass

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: French
• Weight: 36 KB
• Volume: 115
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.20833

✦ Synopsis

Dear Sir,

Our study is a meta-analysis of published research reports on the association of IGF-I with breast cancer risk. We did not focus on testosterone's link to breast cancer. Our analysis showed that levels of Insulin-Like Growth Factor-I (IGF-I) and IGF binding protein-3 (IGFBP-3) were higher in breast cancer patients than in controls especially for pre-menopausal women. 1 These results support the suggested association between high IGF-1 and IGFBP-3 levels and increased risk of breast cancer in premenopausal women, but did not refute the hypothesized link between testosterone and breast cancer.

Other epidemiological studies, including ours, 2 have suggested that plasma levels of testosterone were significantly associated with breast cancer risk both in pre-and postmenopausal women. With increasing testosterone levels in the cir-culation, there was a significant trend for an increase in breast cancer risk. The risk was doubled when women had upper tertile of testosterone compared to those with lower tertile, and the association was sustained when adjusting for other risk factors or covariables. A synergistic effect of IGF and sex steroids on breast cancer risk was also suggested in our study. Many factors are involved in the development of breast cancer. As Mr. Howard mentions in his comments, it is possible that increased testosterone levels may be involved in the initiation of breast cancer. Clearly, more studies are needed to further clarify this issue.