Although androgens (male hormones) have been the central hypothesis in prostate cancer etiology for decades, epidemiologic studies in humans have not been able to confirm this hormonal hypothesis. Most of the studies used sere (blood) to examine the relationships of circulating hormones with subsequent prostate cancer risk. However, it is possible that circulating levels of hormones may not reflect intraprostatic and androgenic activity accurately.
To gain further insights and to provide directions for future epidemiologic studies, the National Cancer Institute (NCI) is conducting a comprehensive methodological study called Intraprostatic androgenicity in relation to circulating levels of hormone and polymorphisms of hormone-related genes: a methodologic study. The specific aims of this study are:
* to correlate circulating levels of androgens and estrogens with tissue levels (including testosterone, DHT, DHT sulfate, androstenedione, androstanediol glucuronide, estradiol, estrone, and estrone sulfate);
* to determine whether the serum-tissue correlation is mediated by age, race, and selected epidemiologic factors, such as smoking and body size;
* to determine whether tissue hormone levels correlate with polymorphisms of certain hormone-related genes, including androgen receptor (AR) and SRD5A2; and
* to correlate circulating levels of hormones with intraprostatic androgenicity, as defined by the combined levels of tissue hormones, androgen receptor, and its associated protein (ARA70).
