Prostatic acid phosphatase and Prostate-specific antigen (PAP and PSA)

Prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA) are two prominent prostate-restricted proteins that function as both diagnostic biomarkers and therapeutic targets in prostate cancer [1, 5]. PAP is a glycoprotein with phosphatase and 5'-nucleotidase activity, while PSA is a serine protease of the kallikrein family (KLK3) primarily involved in the liquefaction of the seminal coagulum [18, 19]. Both antigens are highly expressed in normal prostate tissue and are significantly overexpressed or shed into the circulation in the context of prostate malignancy [9, 24]. PAP is the specific target of Sipuleucel-T, the first FDA-approved autologous cellular immunotherapy, which uses a fusion protein (PA2024) to activate a patient's own antigen-presenting cells [4, 8]. PSA is the most widely used biomarker for prostate cancer screening and monitoring, and it has been targeted in various investigational vaccines, such as PROSTVAC, to elicit a cytotoxic T-cell response against tumor cells [2, 11]. Together, these antigens represent the cornerstone of prostate-specific immune-oncology strategies [1, 16].

Other names

ACPPKLK3Kallikrein-3SemenogelaseAcid phosphatase, prostateProstate-specific antigen

Active immunotherapy involving the activation of antigen-presenting cells and subsequent induction of antigen-specific T-cell and humoral immune responses against prostate cancer cells.