Stimulation of phagocytic activity of neutrophilic granulocytes by sera of patients with solid tumors

The effect of serum of patients with solid tumors on the phagocytic activity of normal neutrophilic granulocytes was investigated. The largest groups of tumors studied were carcinoma of colon/rectum, sarcomas and melanomas. Sera from all three groups of patients were found to have highly significant (p < 0.001) stimulatory effects on granulocyte phagocytic activity. These findings contrast with previously reported depression of granulocyte phagocytic activity associated with various forms of leukemia and lymphomas.