Prostate-specific antigen (PSA) is a valuable tumor marker for the diagnosis and management of prostate cancer. The name was intended to underscore the tissue specificity of this protein because it was believed to be produced exclusively by the epithelial cells of the prostate gland. This knowledge was established on the basis of initial studies in which PSA immunoreactivity detected by immunohistochemistry or immunoassay was found only in normal or malignant prostatic tissue.<sup>53 Oesterling J.E. Prostate specific antigen: A critical assessment of the most useful tumor marker for adenocarcinoma of the prostate J Urol 1989 ;  145 : 907-923

Cliccare qui per andare alla sezione Riferimenti</sup> Because of the clinical significance of PSA, however, the study of this molecule has increased substantially in the last 10 years. It is now clear that PSA is not tissue specific. In this review, we focus on the most recent findings of PSA in nonprostatic tissues, and we discuss the possible physiologic role of PSA and its potential for clinical applications in diseases other than those of the prostate.