[Possible value of positive PSA levels in malignant and nonmalignant breast diseases]

Measurement of serum levels of PSA is widely used as a screening tool for prostate cancer. PSA has been shown to be associated with malignancies of many other organs than prostate, including the female breast. Therefore, PSA is not prostate-specific. PSA serum levels in females increase with excess of androgens. Variable PSA expression was observed in membranes of adipocytes of fat tissue and in the endothelium of small vessels in female and male breast. There is increasing evidence that androgens play a significant role in the development and progression of breast cancer. 5alpha-reductase is an enzyme that is expressed in androgen-dependent tissues, including the female breast, catalyzing the reduction of testosterone to its more bioactive form, dihydrotestosterone, which then transactivates a number of genes. One of these genes encodes for PSA, a favorable prognostic factor in breast cancer. Interactions of PSA and sex hormones in physiological processes and in prostatic and mammary cancer have been reported. The possible influence of PSA on breast cancer growth and progression and even its physiological functions are still under controversial debate. There are some findings which might indicate similarities in the influence of steroid hormones on the development of prostate and breast malignancies, perhaps a unique hormone-dependent molecular pathway for both types of cancer.