Interaction between estrogens and androgen receptor genes microsatellites, prostate-specific antigen and androgen receptor expressions in breast cancer

Researchers are trying to discover new biomarkers for diagnosis, prognosis, treatment monitoring and to develop new drugs that might work better against breast cancer. An example in this context is the identification of PSA (prostatespecific antigen) in normal and tumoral mammary gland. PSA (hK3), a 240 amino acids 33-kDa single-chain glycoprotein is one of the human kallikreins expressed at high levels in the epithelium of the human prostate gland. PSA gene is the best-characterized AR (androgen receptor) regulated gene and PSA protein is an important clinical marker used for prostate cancer screening, diagnosis, prognosis and monitoring. Previous studies showed that PSA is expressed in a considerable proportion of female breast cancers, ranging from 9.3% to 49% [1–5], but the functional role and the clinical significance of extraprostatic PSA were not defined yet. PSA, like other proteases can digest insulin-like growth factor-binding proteins, leading to the release of growth factors [6]. Digestion of the basal membrane and extracellular matrix proteins might facilitate cell migration and invasion. However, PSA inhibits the endothelial cell response to angiogenic stimulation by fibroblast growth factor-2 and vascular endothelial growth factor, suggesting that PSA might be an endogenous anti-angiogenic compound [7]. Lai et al. [8] reported that PSA stimulates the conversion of the potent estradiol to the less potent estrone, inhibiting the growth of certain breast cancer cell lines in vitro. This might contribute Interaction between estrogens and androgen receptor genes microsatellites, prostate-specific antigen and androgen receptor expressions in breast cancer