Prostate-specific acid phosphatase (PSAP), also known as prostatic acid phosphatase (PAP), is a glycoprotein enzyme primarily produced by prostate epithelial cells. Historically, it was one of the first identified prostate-specific biomarkers, playing a role in phosphate metabolism and cellular signaling. PSAP is secreted into seminal fluid and, to a lesser extent, enters circulation. While its physiological function remains partially understood, PSAP has been implicated in sperm motility regulation and immune modulation.
In clinical contexts, PSAP gained prominence as a diagnostic and prognostic marker for prostate cancer before the advent of prostate-specific antigen (PSA) testing. Elevated serum PSAP levels correlate with tumor progression and metastasis. However, due to lower specificity compared to PSA, its diagnostic use has declined. Recent research revisits PSAP in advanced prostate cancer contexts, particularly neuroendocrine variants, where it may serve as a therapeutic target.
PSAP antibodies are critical tools in research and diagnostics. They enable immunohistochemical detection of PSAP in tissue samples, aiding in prostate cancer identification and subtyping. Therapeutic applications are emerging, including antibody-drug conjugates (ADCs) targeting PSAP-expressing tumors. Additionally, PSAP's immunomodulatory properties have spurred interest in immunotherapy combinations. Ongoing studies explore its role in tumor microenvironment interactions, potentially unveiling novel therapeutic avenues.