Kallikrein-3 (Prostate-specific antigen) (PSA)

Kallikrein-3, commonly known as Prostate-specific antigen (PSA), is a 34-kDa serine protease primarily produced by the epithelial cells of the prostate gland [UniProt: P07288]. Its physiological role involves the liquefaction of the seminal coagulum by cleaving proteins like semenogelin, which is essential for sperm motility [NCBI Gene: 354]. In the context of disease, PSA is the most widely used clinical biomarker for the screening and monitoring of prostate cancer, as its levels in the blood increase when the normal prostate architecture is disrupted by malignancy or inflammation [NIH: National Cancer Institute]. Beyond its diagnostic utility, PSA is a target for immunotherapy, where vaccines such as PROSTVAC-VF are designed to stimulate the immune system to recognize and eliminate PSA-expressing cancer cells [PubMed: 20406920]. These therapies aim to harness the restricted expression pattern of PSA to direct cytotoxic T-lymphocytes specifically toward prostatic tumor tissue [StatPearls: Prostate Cancer].

Other names

PSASemininP-30 antigenGamma-seminoproteinKallikrein-related peptidase 3KLK3

Vaccines and immunotherapies targeting PSA function by inducing a specific T-cell response against cells that process and present PSA-derived peptides on their surface, leading to immune-mediated cell death [PubMed: 25583304].