The proposed work is based on our observations that human blood group MN precursors, T (Thomsen-Friedenreich) and Tn (precursor of T) antigens are human carcinoma associated and that T antigen present on human breast carcinomata elicits both humoral and cell-mediated immune responses in patients with these malignancies. We will perform the leukocyte migration inhibition assay in agarose with T antigen on a large population of breast carcinoma patients and include a comparable population of similar size consisting of patients with benign breast disease as well as of apparently healthy people. We will also test patients with carcinomata of the gastrointestinal tract and lung for their cellular immune responses to T antigen since we found such carcinomata also to contain T-specific antigen. We intend to evaluate the specificity and sensitivity of leukocyte adherence inhibition assay in comparison with other methods for measuring cell-mediated immunity. We plan to investigate more patients with carcinomata of the gastrointestinal tract and lung, for their serum anti-T antibody levels. We hope to complete establishment of a method for rapid quantitation of T-specific structures in human body fluids. We will isolate and characterize T- and Tn- specific structures from human breast carcinoma tissues.