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

PSA- and PAP-expressing prostate cancer cells are the primary targets for several immunotherapeutic approaches in the treatment of prostate cancer. These cells are defined by the expression of two key antigens: Prostate-Specific Antigen (PSA), a serine protease (KLK3) involved in seminal fluid liquefaction, and Prostatic Acid Phosphatase (PAP), a phosphatase (ACPP) that regulates cell growth. Both antigens are highly specific to prostate tissue and are overexpressed in malignant states, providing a basis for targeted immune responses. Drugs such as Sipuleucel-T (Provenge) and PROSTVAC utilize these antigens to prime the immune system, specifically activating T cells to recognize and lyse the cancer cells. While PSA is the most common biomarker for monitoring disease progression, PAP has regained interest as a therapeutic target due to its persistence in advanced disease. Therapeutic challenges include the immunosuppressive tumor microenvironment and the potential for antigen downregulation, which can lead to immune escape.

Other names

PSA-expressing prostate cancer cellsPAP-expressing prostate cancer cellsKLK3 and ACPPProstate cancer cells

Active immunotherapy, Vaccine-mediated T-cell activation, Dendritic cell-mediated antigen presentation