Gamma-glutamyltranspeptidase levels as an aid in the management of human cancer.

Plasma gamma-glutamyltranspeptidase (GGTP) levels were measured in 435 cancer patients, 120 healthy controls, 15 patients with systemic lupus erythematosis, and 10 patients with rheumatoid arthritis. The mean GGTP activity of all cancer patients studied, with the exception of malignant lymphoma, was significantly elevated compared to control values. Several patient groups were retrospectively analyzed to determine whether GGTP levels correlated with clinical status. Patients who were disease-free had GGTP levels in the normal range, whereas patients with metastases had elevated levels. Serially increasing GGTP levels were associated with disease progression and death. Persons who remained free of disease had serial GGTP levels within the normal range. Furthermore, decreasing levels were associated with response to therapy. These results indicate that GGTP levels may have prognostic value in various human malignancies.