BACKGROUND: Early detection of
prostate cancer (CaP), the most
prevalent cancer and the second-leading cause of death in men, has proved difficult, and current detection methods are inadequate.
Prostate-specific antigen (PSA) testing is a significant advance for early diagnosis of patients with CaP. CONTENT: PSA is produced almost exclusively in the
prostate, and abnormalities of this
organ are frequently associated with increased serum concentrations. Because of PSA's lack of specificity for CaP, however, many patients undergo unnecessary
biopsies or treatments for
benign or latent
tumors, respectively. Thus, a more specific method of CaP detection is required to augment or replace screening with PSA. The focus recently has been on creating
cost-effective assays for circulating protein biomarkers in the
blood, but because of the
heterogeneity of CaP, it has become clear that this effort will be a formidable challenge. Each marker will require proper validation to ensure clinical
utility. Although much work has been done on variations of the
PSA test (i.e., velocity,
density, free vs bound, proisoforms) with limited
usefulness, there are many emerging markers at various stages of development that show some promise for CaP diagnosis. These markers include kallikrein-related
peptidase 2 (
KLK2), early
prostate cancer antigen (EPCA),
PCA3, hepsin,
prostate stem cell antigen, and
alpha-methylacyl-CoA racemase (
AMACR). We review biomarkers under investigation for the early diagnosis and management of
prostate cancer. SUMMARY: It is hoped that the use of panels of markers can improve CaP diagnosis and prognosis and help predict the therapeutic response in CaP patients.
