Summary Blood samples were collected from 52 incident cases of histologically confirmed prostate cancer, an equal number of cases of benign prostatic hyperplasia (BPH) and an equal number of apparently healthy control subjects. The three groups were matched for age and town of residence in the greater Athens area. Steroid hormones, sex hormone-binding globulin, and insulin-like growth factor 1 (IGF-1) were measured in duplicate by radioimmunoassay in a specialized US centre. Statistical analyses were performed using multiple logistical regression. The results for IGF-1 in relation to prostate cancer and BPH were adjusted for demographic and anthropometric factors, as well as for the other measured hormones. There was no relation between IGF-1 and BPH, but increased values of this hormone were associated with increased risk of prostate cancer; an increment of 60 ng ml-' corresponded to an odds ratio of 1.91 with a 95% confidence interval of 1.00-3.73. There was also some evidence for an interaction between high levels of testosterone and IGF-1 in relation to prostate cancer. This finding suggests that, in addition to testosterone, IGF-1 may increase the risk of prostate cancer in humans.Insulin-like growth factor 1 (IGF-1) is secreted mainly by the liver but is also produced in several other tissues in response to growth hormone (LeRoith et al, 1992). It has been documented that IGF-1 can act in an autocrine and paracrine manner to promote normal growth and malignant cellular proliferation (Daughaday, 1990;LeRoith et al, 1992). The importance of IGF-1 as a major growthregulating molecule has been established for cells in culture (Goustin et al, 1986;LeRoith et al, 1992; Webster et al, 1996) and has also been suggested by studies in vivo (Ezzat and Melmed, 1991). IGF-1 and several of its binding proteins are produced by normal prostate cells (Cohen et al, 1991) as well as prostate cancer cells (Pietrzjowski et al, 1993;Kimura et al, 1996) and act locally through activation of IGF-1 receptors to stimulate cell proliferation (Angelloz-Nicoud and Binoux, 1995). In addition to its established autocrine and paracrine action, IGF-1 has important endocrine functions (LeRoith et al, 1992). However, the role, if any, of circulating IGF-1 in the aetiology of benign prostatic hyperplasia (BPH) and prostate cancer has not received sufficient attention.We have previously reported results concerning the role of serum steroid hormones in the aetiology of BPH and prostate cancer ) from a matched case-control study undertaken in Athens, Greece. Circulating IGF-1 was measured in the same sera, and we present the relevant results in this report.
SUBJECTS AND METHODSIn the context of a large, ongoing case-control study of diet in relation to prostate cancer and BPH, blood samples were collected during an 18-months period from 52 incident cases of histologically confirmed prostate cancer and 52 cases of BPH with matching for age (±1 year) and town of residence within the greater Athens area. Within the constraints imposed by this ...