[Determination of acid phosphatase in prostatic carcinoma]

Serum acid phosphatase activity is the most commonly measured biochemical marker for diagnosing prostatic cancer and monitoring responses of such patients to therapy. Increased total serum acid phosphatase activity has been detected in the serum of up to 75% of patients with advanced disease (Stage D) which has metastasized to the bone, whereas in early stages (Stage A and B) as few as 10% may have increased total serum acid enzyme phosphatase values that can be detected by conventional biochemical assays. Serum acid phosphatase is believed to be comprised of specific molecular variants (isoenzymes) from sources throughout the body. Unfortunately, biochemical tests may lack specificity and sensitivity for the prostatic acid phosphatase, which is, thought to enter the serum in early stages of prostatic cancer. This situation prompted the development of immunologic assays for the determination prostatic acid phosphatase (radioimmunoassays, enzyme-immunoassays) which, it is hoped, combine the specificity achieved with immunologic reagents and techniques with the sensitivity made available through the use of radioisotopes or spectrophotometers.