PSA and acid phosphatase in the diagnosis of prostate cancer

Prostate specific antigen (PSA) and prostate acid phosphatase (PAP) are two well known markers for prostate cancer, PSA was isolated in 1979 and is biochemically a 33-kDa serine protease and in isomeric form. The PSA blood test was developed in 1980 and has been most useful in the: staging, monitoring, and early detection of recurrent: disease, PSA is of greatest value as a screening aid for the early detection of prostate cancer, Early-stage, organ-confined, nonpalpable, and clinically significant, but curable prostate tumors, have been detected by PSA and digital rectal examination. Several derivative PSA Bests, such as PSA velocity or slope, PSA density or index, age-specific referenced PSA ranges, and free versus complexed PSA have been examined to improve the diagnostic accuracy of PSA, Age-and race-specific PSA ranges and free PSA appear to enhance the ability of PSA to differentiate prostate canter from benign prostatic hypertrophy, but large statistically valid trials are still needed. The PSA immunohistochemical test was developed in 1981 to detect secondary metastasis: of prostate carcinoma. Detection of micrometastasis also has been improved. by reverse transcriptase (RT)-polymerase chain reaction (PCR) of PSA-containing prostate cells in circulation, bone narrow, and lymph nodes. RT-PCR is still an experimental tool at present, Prostate acid phosphatase (PAP) is the old "gold standard" for prostate cancer. Overall, PSA is a better disease parameter than PAP. However, recent investigations on the basic biochemistry and molecular biology of PAP have provided new insight into its potential role in the diagnosis and therapeutic monitoring of prostate cancer.