Biochemical and clinical studies of aldolase isozymes in human cancer.

Radioimmunoassays specific for ALD isozymes were developed for the quantification of human ALD-A, -B, and -C. The method is a double antibody radioimmunoassay consisting of purified radioiodinated ALD-A, -B, and C as ligand, chicken antibodies to ALD-A, -B, and -C, and rabbit antibodies to chicken IgG. The Iodogen method was used for the iodination of the purified isozymes. ALD-A was present in high concentration in muscle, ALD-B in adult liver, and ALD-C in adult brain. ALD-A was elevated in hepatoma tissue and hepatoma cell lines, whereas ALD-B was distinctly low. Normal serum levels for the three isozymes were determined. The ALD-A level in the serum from 41 normal subjects was 170 +/- 39 ng/ml. Serum ALD-A level was increased in many patients with cancer and muscle diseases, but not in patients with hepatitis or other benign diseases. Serum ALD-B level in 11 normal subjects was 28.5 +/- 9.2 ng/ml. Serum ALD-C level in 12 normal subjects was 2.4 +/- 0.7 ng/ml. The determination of ALD-A, -B, and -C by radioimmunoassay may be a valuable tool in biochemical and clinical studies of these isozymes.