The serum inhibitor activities of granulocyte-macrophage colony formation were evaluated by the in vitro culture technique in 60 patients with cancer and control subjects including 24 normal adults and 27 patients with a variety of nonneoplastic disorders. The inhibitor activity in cancer patients (mean, 59%) was significantly higher (p < 0.001) than was that in normal adults (mean, 31%) and patients with nonneoplastic diseases (mean, 36%). There was no difference in the inhibitor activity between the latter two groups of subjects. There was no correlation between the serum inhibitor activity in cancer patients and the histological type or primary site of tumor, the estimated duration or extent of disease, and serum albumin levels. Preliminary observations indicated that the inhibitor activity may be associated with serum lipoproteins. There was no significant difference in serum colony-stimulating activity among cancer patients, normal control subjects, and patients with nonneoplastic diseases.
Supported in part by the American Cancer Society Institutional Grant IN-111A.