Leukocyte adherence inhibition by soluble tumor antigens in breast cancer patients.

The authors modified and refined the Leukocyte Adherence Inhibition Assay (LAI) first described by Halliday, et al. in 1972 by standardizing the protein concentration of tumor-associated antigens (TAA) and by utilizing paired normal tissue extracts as controls to eliminate interference of HL-A histocompatibility antigens and organ-associated antigens. When dose response studies were performed, a progressively larger percentage of patients reacted to the LAI test with increasing concentration of tumor extracts, but the optimal concentration was found to be 200 mug/ml, where 42 out of 66 (63%) leukocytes from 54 breast cancer patients reacted to the breast cancer extracts. At this dose range, only three out of 39 (7%) normal donors and four out of 30 (13%) patients with other types of cancer were positive. When breast cancer patients were tested against TAA of colon cancer and malignant melanoma, one of 24 (4%) and two of 24 (8%), respectively, were positive. Although a higher response rate (72%) was noted in Stage II disease, this was not statistically different from Stage I and Stage III disease. Likewise, no difference was noted in LAI at varying phases following the mastectomy.