Acid phosphatase (ACP)

Abstract

The acid phosphatases are a group of enzymes capable of hydrolyzing esters of orthophosphoric acid in an acid medium. Acid phosphatase activity is widely distributed in human tissues and acid phosphatases represent a heterogeneous group of enzymes containing many isoenzymes, each specific for one type of tissue. The human prostate is particularly rich in this enzyme (PAP) and serum enzyme levels have been used as a tumor marker of prostate cancer. While PAP was markedly increased in patients with bone metastases of prostate cancer, it is unable to detect earlier stage tumors reliably. The sensitivity and specificity of serum acid phosphatases and PAP are low in diagnosing, staging and following patients with prostate cancer. Presently, prostate-specific antigen (PSA) is superior to PAP for diagnosis, screening, and monitoring prostate cancer. PAP may have an adjuvant value in the management of prostate cancer because a combination of PSA and PAP testing has revealed a high sensitivity and specificity in detecting prostate cancer.