Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0282612 (PIN)
 2,291 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prostate-specific antigen is a kallikrein-like serine protease that is produced exclusively by the epithelial cells of all types of prostatic tissue, benign and malignant. Physiologically, it is present in the seminal fluid at high concentration and functions to cleave the high molecular weight protein responsible for the seminal coagulum into smaller polypeptides. This action results in liquefaction of the coagulum. Prostate-specific antigen is also present in the serum and can be measured reliably by several different assays. Although the protein is prostate-specific, it is not prostate-cancer-specific. As a result, benign conditions such as benign prostatic hyperplasia, prostatitis and infarction, as well as prostatic intraepithelial neoplasia, can be associated with elevated serum levels of prostate-specific antigen. Approximately 25% of men with benign prostatic hyperplasia have an elevated serum value of prostate-specific antigen, whereas 35% to 40% of patients with organ-confined prostate cancer have a level within the reference range. Prostate-specific antigen can identify some cancers not detectable by digital rectal examination; alternatively, this examination can identify cancers not detectable from the serum prostate-specific antigen concentration. Thus, the most complete evaluation of the prostate gland is achieved when both the prostate-specific antigen value and the digital rectal examination are used. The density and the rate of change of serum prostate-specific antigen are new concepts to improve the ability of prostate-specific antigen to detect early prostate cancer. Preliminary results are encouraging, but additional studies are required to determine the true usefulness of these new variables. Thus, in 1992, determination of the prostate-specific antigen value is a valuable new tool for the practicing physician and will be instrumental in our campaign to diagnose clinically significant prostate cancer at an early, curable stage.
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PMID:Prostate-specific antigen and diagnosing early malignancies of the prostate. 128 95

Human prostatic epithelial cells constitutively secrete prostate-specific antigen (PSA), a kallikrein-like serine protease, which is a normal component of the seminal plasma. PSA is currently used as a specific diagnostic marker for the early detection of prostate cancer. We demonstrate that PSA degrades extracellular matrix glycoproteins fibronectin and laminin and, thus, may facilitate invasion by prostate cancer cells. Blocking PSA proteolytic activity with PSA-specific mAb results in a dose-dependent decrease in vitro in the invasion of the reconstituted basement membrane Matrigel by LNCaP human prostate carcinoma cells which secrete high levels of PSA. A novel PSA-SDS-PAGE zymography method for the detection of matrix degrading ability of PSA is also described. We propose that: (a) because of the dysplastic cellular disorganization in early neoplastic lesions called prostatic intraepithelial neoplasia (PIN), PSA may be secreted not only at the luminal end but also, abnormally, at the cell-basement membrane interface, causing matrix degradation and facilitating invasion; and (b) PSA, along with urokinase, another serine protease secreted by prostatic epithelium, may be involved in the proteolytic cascade during prostate cancer invasion and metastasis. The discovery of the extracellular matrix degrading ability of PSA not only makes it a marker for early detection but also a target for prevention and intervention in prostate cancer.
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PMID:Prostate-specific antigen, a serine protease, facilitates human prostate cancer cell invasion. 981 98