Biomarkers have an important role in many diseases, including prostate cancer. No 2 patients’ cancers are the same and biomarkers can provide valuable information to help health care professionals make more informed treatment decisions for individual patients.1
Frequently found in the blood and other body tissues and fluids, biomarkers are biological markers of disease. Some biomarkers can be used in diagnostic testing; they are measured, often using a blood test, and, if present, can be a sign of a condition or disease.1 Other biomarkers can also be used as targets for treatment.2
One biomarker that men with prostate cancer will no doubt be familiar with is PSA, or prostate-specific antigen. PSA is a protein produced by the prostate gland that is released into the circulation,3 where it can be measured using a simple blood test.4
Men are encouraged to “know their PSA” as raised levels can be an indicator of prostate cancer.4 PSA levels are also measured regularly in men who have already been diagnosed with prostate cancer because an increase in the amount of PSA in the blood can be a sign of disease progression or recurrence.4
Like PSA, PSMA, or prostate-specific membrane antigen, is a protein. PSMA is often found in higher amounts on the surface of prostate cancer cells as compared to normal cells.5
As the name suggests, PSMA remains attached to the cell surface,6 known as the cell membrane, rather than being released into the bloodstream. This location of PSMA attached to the cell surface, coupled with its high expression in prostate cancer cells, raises the prospect of using this biomarker to pinpoint the exact location of prostate cancer cells anywhere in the body.7
This could help in recognizing advanced disease, which has spread (metastasized) to other parts of the body. This is an important prospect as knowing whether cancer has metastasized is crucial for determining the appropriate treatment strategy.7,8
Similarly, while some forms of prostate cancer grow slowly, others may have spread beyond the prostate. Testing could identify stage, grade, and risk. These factors might help determine what comes next.9 Data from scientific studies have shown that PSMA levels are higher in advanced prostate cancer.10,11 PSMA could potentially be used to identify those cancers that are advancing and require treatment.7
Cancer treatments continue to advance and, across oncology, targeted treatments with the ability to kill cancerous cells, while aiming to minimize damage to surrounding tissue, are being pioneered.2 Treatments must try to exploit features that are unique to cancer cells, such as a specific protein that, like PSMA, is expressed on the cancer cell surface more abundantly than in normal cells.2,6
Whatever the future holds for this biomarker, in diagnosing or in determining potential treatment, it is clear that PSMA is something that everyone treating or living with prostate cancer is going to be hearing a lot more about over the coming months and years. Research and clinical trials mean that our knowledge base is expanding all the time. Please speak to your health care professional to find out more about the management of your prostate cancer.
This content has been developed by Advanced Accelerator Applications, a Novartis Company.
1. National Cancer Institute. Biomarker. https://www.cancer.gov/publications/dictionaries/cancerterms/ def/biomarker. Accessed November 2020.
2. National Cancer Institute. Targeted cancer therapies. https://www.cancer.gov/about-cancer/treatment/types/targeted-therapies/targeted-therapiesfact- sheet. Accessed November 2020.
3. National Cancer Institute. PSA. https://www.cancer.gov/publications/dictionaries/cancerterms/ def/psa. Accessed November 2020.
4. National Cancer Institute. Prostate-specific antigen (PSA) test. https://www.cancer.gov/types/prostate/psa-fact-sheet. Accessed November 2020.
5. Sokoloff RL, Norton KC, Gasior CL, et al. A dual-monoclonal sandwich assay for prostate-specific membrane antigen: levels in tissues, seminal fluid and urine. Prostate. 2000;43:150-157.
6. Israeli RS, Powell TC, Fair WR, Heston WDW. Molecular cloning of a complementary DNA encoding a prostate-specific membrane antigen. Cancer Res. 1993;53:227-230.
7. Hofman MS, Lawrentschuk N, Francis RJ, et al. Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy (proPSMA): a prospective randomised, multi-centre study. Lancet. 2020;395:1208-1216.
8. National Cancer Institute. Advanced cancer. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/advanced-cancer. Accessed November 2020.
9. American Cancer Society. If you have prostate cancer. https://www.cancer.org/cancer/prostatecancer/ if-you-have-prostate-cancer.html. Accessed September 2020.
10. Ross JS, Sheehan CE, Fisher HAG, et al. Correlation of primary tumour prostate-specific membrane antigen expression with disease recurrence in prostate cancer. Clin Cancer Res. 2003;9:6357-6362.
11. Bostwick DG, Pacelli A, Blute M, et al. Prostate specific membrane antigen expression in prostatic intraepithelial neoplasia and adenocarcinoma. Cancer. 1998;82:2256-2261.