Enzymatic and Immunological Studies of Prostatic Acid Phosphatase

Levels of serum acid phosphatase are elevated in prostatic cancer patients as compared with those of normal human. Prostatic cancer patients with bone metastasis show about 2 to 5 fold increased activities of serum acid phosphatase while patients without bone metastasis show slight increase (about 20%) of the activity. When we analysed serum acid phosphatase isozyme pattern with DEAE cellulose column chromatography, profiles of these enzymes of normal and prostatic cancer patients differ greatly. In normal human, three distinct isozymes I, II and III of serum acid phosphatase were observed. Acid phosphatase of prostatic adenoma tissue surgically removed from prostatic hypertrophy patients consists of two isozymes II and III which are chromatographically corresponding to those isozymes of serum acid phosphatase. Serological analyses and inhibitor- enzyme specificities led us to conclude that serum isozymes II and III are derived from prostatic gland. In cancer patients without bone metastasis, a greatly increased activity of isozyme III and normal level of isozyme II in serum acid phosphatase were observed. However in prostatic cancer patient with advanced bone metastasis, a huge increase of serum isozyme II activity was observed whereas isozyme III is at an undertectable level. These isozyme variations in serum acid phosphatase suggest that assay of each isozyme is a valuable approach for diagnosis and judgement of prognosis of prostatic cancer