Detection of human tumor-associated antigens by the leukocyte migration in agarose assay

Twenty-three of 36 (64%) lung cancer patients, 19 of 36 (54%) melanoma patients and 18 of 27 (66%) sarcoma patients tested in the leukocyte migration in agarose assay against soluble extracts of histologically similar tumors showed significant inhibition of leukocyte migration. Reactivity to extracts of dissimilar tumors was low. Sera of only 1/13 (7%) lung cancer patients, 2/19 (10%) melanoma patients and 7/21 (33%) sarcoma patients were inhibited by extracts of histologically dissimilar tumors. Only 7-9% of cancer patients reacted to paired extracts of normal tissue from the tumor donors. An average of 13% of sera from normal controls reacted to tumor extracts. Stage of disease and mode of therapy appeared to have little effect on overall reactivity in this assay, although the number of patients within the various categories was small for purposes of statistical analysis. The leukocyte migration in agarose assay shows a sensitivity and specificity to tumor-associated antigens comparable to that of the older capillary tube method in general use and may facilitate performance of migration inhibition. This assay may not be useful as a prognostic test due to the lack ofcorrelation with stage of disease and treatment modality. However, its high specificity and economical use of tumor antigen suggest applications in tumor antigen purification. The use of soluble tumor antigen preparations may make it possible to purify these antigens further to increase specificity and reactivity.