Definiti​on

Prostate-specific antigen (PSA), also known as kallikrein-3 (KLK3) or P-30 antigen, is a glycoprotein enzyme encoded by the KLK3 gene. PSA is a member of the kallikrein-associated peptidase family and is secreted by prostate epithelial cells. PSA is produced for semen, which liquefies semen in semen coagulate, allowing sperm to swim freely. It is also believed to help dissolve cervical mucus, allowing sperm to enter the uterus. A small amount of PSA is present in the serum of healthy men with a healthy prostate, but in the case of prostate cancer or other prostate diseases, PSA is usually elevated with prostate-specific antigen (PSA) and is not the only indicator of prostate cancer, but prostatitis or benign prostatic hyperplasia may also be detected. Wang separated PSA from prostate extract in 1979[2], and used it for the first time in clinic in 1986, and soon replaced prostate Acid phosphatase as the most important prostate cancer. PSA is a Serine protease with a molecular weight of 34000, a sugar content of 7%, and a pl=6.9. The concentration of PSA in semen is 0.2~0.5mg/ml, and the concentration in serum is only one millionth of that in semen.

PSA in blood is the sum of free PSA and bound PSA, also known as total PSA, and is expressed as TPSA. In men with prostate cancer, the ratio of free (unbound) PSA to total PSA decreases.

Fig. 1 Structure of PSA.

Fig. 2 PAS-Test

Function

Prostate-specific antigen (PSA) is a glycoprotein produced by the epithelial cells lining the prostate ducts and acinars. Normally, it is secreted into the prostate ducts and is only present in prostate tissue, prostate fluid, and seminal plasma. PSA is produced by normal, hyperplastic, and cancerous prostate tissue. PSA is used as a tumor marker in other areas of early detection of prostate cancer and management of prostate disease. The Prostate-Specific Antigen Best Practice Statement: 2009 Update described the function of PSA testing for:

-- Assess a man's risk of prostate cancer

-- Assist with pretreatment staging

-- Risk assessment, post-treatment monitoring

-- As a guideline for the management of relapse after primary or secondary treatment in men

Compare FPSA and TPSA

Comparing the test results of total PSA and free PSA can give doctors an idea of how likely a person is to develop prostate cancer.

The range of free PSA may vary, but in general, a higher ratio of free PSA to total PSA indicates a lower risk of prostate cancer. On the other hand, a lower ratio of free PSA to total PSA indicates a higher risk of prostate cancer.

However, PSA testing alone does not confirm the diseases, as other factors can also affect PSA levels. A digital rectal examination (DRE) and prostate biopsy may also be necessary.

TPSA ​and Prostate Cancer

The expression of PSA protein is not specific for prostate cancer. Specific prostate epithelial cells in a variety of conditions, including normal and proliferative states. However, under normal circumstances, almost all PSA proteins are secreted into semen, and in prostate cancer, PSA proteins leak into the bloodstream. Therefore, serum PSA measurement is of great significance for the observation of prostate cancer. It is widely used as a blood marker for prostate cancer to screen for and detect recurrence after treatment. The higher the serum PSA level, the more likely it is to be with prostate cancer. The detection rate of prostate cancer with PSA 4.1 ~10 ng/ml is 20 ~ 30%, and the detection rate of prostate cancer with PSA≥10 ng/ml is 30 ~ 50%. However, it is important to note that about 15% of people with normal PSA and induration of the prostate found on digital rectal examination (DRE) were found to be cancerous.

Clinical Application

PSA screening has led to a significant increase in the incidence of prostate cancer (PC). This increase in detection rates has led to a significant decrease in the incidence of advanced pancreatic cancer, and most new pancreatic cancers today are localized tumors with a high probability of cure.

Tumor labeling laboratories primarily use total PSA (prostate-specific antigen) to treat cancer. It is used as a diagnostic test along with free PSA and free to total PSA ratio. It is of great value in detecting metastatic or persistent disease after treatment. Persistently elevated or elevated levels after treatment indicate disease recurrence or residual disease.

Alpha Lifetech Inc. is dedicated to developing tPSA diagnostic regents. Alpha Lifetech Inc. is a reputable supplier focusing on research, manufacture and sales of In Vitro Diagnostic (IVD) regents. All the IVD regents offered by Alpha Lifetech Inc. have undergone strict QC validation and are certified by the COA (certificate of analysis). Meanwhile, we can provide customized services according to customers' requirements. Alpha Lifetech Inc. is committed to supply high-quality, high-sensitivity antigen and antibody products for scientific research and industrial customers. In addition to regular small packages, Alpha Lifetech Inc.'s large-scale fermentation platform also allows us to provide raw material-grade IVD regents for the majority of industrial customers.

Please feel free to call our sales manager for technical information and quotation!