Leukocyte adherence inhibition: tumor specificity of cellular and serum-blocking reactions in human melanoma, breast cancer, and colorectal cancer.

Blood samples were obtained from hosptial patients suspected of having cancer (colorectal carcinoma, breast carcinoma, or melanoma) or from patients after surgical treatment for these cancers. Leukocytes were tested for reactivity with appropriate tumor extracts by leukocyte adherence inhibition (LAI), without knowledge of the diagnosis. Leukocytes from each patient were tested with the specific related extract corresponding to the suspected tumor type and with at least one unrelated extract. Each patient's serum was tested for its effect on the adherence of autologous leukocytes with specific tumor extract. Detailed leukocyte adherence data are presented for each of the 110 patients. Of the 75 patients eventually diagnosed as having cancer of one of the above types, 67 (89.3%) gave positive specific LAI reactions and only 5 (6.7%) reacted nonspecifically. Of the 35 patients with benign, unrelated, or unidentified disease, 10 (28.6%) gave positive reactions; most of these were patients with benign breast disease reacting with breast tumor extract. Leukocyte reactions with related extracts were almost always blocked by autologous serum (only two exceptions). When tested with allogeneic leukocytes reacting with their corresponding extracts, sera never blocked leukocytes of a different tumor type; in some cases they also failed to block leukocytes of the same tumor type although autologous leukocytes were blocked.