PSA (Prostate Specific Antigen) Levels
The serum PSA value is useful for the follow-up and early detection of prostate cancer since the probability of developing prostate cancer increases with higher values. However, since there is no agreed cut-off point, additional tests are often required to establish the diagnosis or to rule out other causes of its increase.
Prostate-specific antigen (PSA) is an enzyme produced by prostate tissue cells whose function is to participate in the dissolution of possible clots in the seminal fluid, and therefore plays an important role in fertility. PSA is found in greater quantities in the seminal fluid, however some of it can escape from the prostate and be released into the serum.
Increased serum PSA levels are associated with prostate cancer. In fact, it has been shown to be superior to other techniques traditionally used for the detection of early prostate cancer, achieving detection rates with a specificity close to 91% when the serum PSA value reaches values above 4 ng/mL. Early prostate cancer is usually asymptomatic and an elevated serum PSA level is often the first indication of cancer. However, there is no specific normal or abnormal blood PSA concentration that can currently serve as a threshold, so an elevated PSA result would recommend a confirmatory test as well as additional tests to confirm the possible diagnosis, as PSA is the only way to confirm the diagnosis.Elevated serum PSA can also be found in a litany of benign conditions, such as infections, trauma, inflammatory processes or benign prostatic hyperplasia (BPH) that can temporarily increase levels. Likewise, decreased values may be present in positive cases of prostate cancer, so monitoring is also recommended for men over 50 years of age, or who have a family history of prostate cancer.
PSA levels can be affected for different reasons, either by a genetic or environmental factor. It is estimated that about 40% of the variability of PSA levels in the general population is due to hereditary factors. Based on a genome-wide association study involving more than 15,000 men, 3 markers associated with variability in PSA levels have been identified. Among the genes involved in this trait we can find the HNF1B gene or the MSMB gene, genes that had been previously associated with the risk of colon cancer, as well as the CLPTM1L gene, also previously associated with the development of different types of cancers.
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