[Serum p2PSA derivative indexes in prostate cancer: an update]

Serum prostate-specific antigen (PSA) is composed of the PSA precursor protein (proPSA) in the absence of the leader peptide induced by human kallikrein 2 (hK2). There are many forms of PSA in the blood, including free PSA and bound PSA. Serum proPSA, as a free PSA, has many isoforms, among which, [-2]proPSA (p2PSA) cannot be activated by hK2 and therefore exists stably in the blood. Serum p2PSA is a homologous isomer of PSA. Serum prostate health index and % p2PSA, as the derivative indexes of p2PSA and molecular markers associated with the development and progression of prostate cancer, can reduce serum PSA test-induced excessive diagnosis and treatment of the malignancy and improve the accuracy of its prediction. This review summarizes recent progress in the studies of serum p2PSA and its derivative indexes in prostate cancer.