Laboratory aids to diagnosis--enzymes.

A summary is presented of those organ specific enzyme assays traditionally used in evaluation of the patient with cancer. In addition, the use of certain serum enzymes such as gamma-glutamyl transpeptidase, phosphohexose isomerase or 5'-nucleotidase as aids in following the course of the disease, particularly in patients with metastatic spread to the liver is outlined. Also considered is the utility of enzyme analysis in biopsy tissue, biologic fluids, and washings of body cavities. Newer enzymes are considered which might, in the future, be developed as diagnostic tools or as probes for the understanding of the etiology of cancer.