A computerized tube leukocyte adherence inhibition assay to detect antitumor immunity in early human cancer: a review of two years' experience.

A 2-year experience with a computerized in vitro assay of leukocyte adherence inhibition (LAI) indicated that patients with cancer of either the colorectum, stomach, pancreas, breast, or lung expressed antitumor immunity to an organ-type specific neoantigen. About 1% of the 1,299 control subjects with benign or malignant disease had a positive LAI assay and 2.5% of patients with inflammatory disease of the colorectum, stomach, pancreas, or lung had a positive LAI assay when tested against tumor extracts of the same organ. Of the 351 patients with cancer of either the colorectum (111), stomach (40), pancreas (28), lung (57), or breast (116) who harbored a microfocus of cancer, 80% or more were LAI positive. As the stage of the cancer advanced, fewer patients were LAI positive. Nine of 45 patients (20%) with colon adenomas had a positive LAI response to colon cancer antigen and 17 of 204 patients (8%) with benign breast disease reacted to the breast cancer antigen. Our results suggested that the leukocytes of some of the LAI-positive patients with either colon adenomas or benign breast disease were responding to an organ-specific neoantigen. Whether the acquisition of a cell surface tumor antigen by the colon adenomas and the dysplastic lesions of the breast implies an irretrievable step to ultimate malignancy is unknown. Most patients exhibit a vigorous antitumor immune response when the cancer exists as a microfocus, and some even before the neoplasm has acquired the capacity to invade.