A new tumor-associated antigen, called Tennessee Antigen (TAG), has been isolated from 95% of 154 primary human gastrointestinal tumors. In 208 patients with colorectal carcinoma 81% showed elevated levels of TAG in their sera. Our Phase I studies have resulted in the production of monoclonal antibodies (MoAb) and the development of an enzyme-linked immunoassay (EIA) to measure TAG in serum. In the present proposal, we will continue to produce and characterize MoAB using Western Blotting, immunofluorescence technique and immunohistochemical staining. The specificity, sensitivity and reproducibility of EIA will be studied. A prototype of TAG-EIA kit will be developed. The clinical utility of the TAG-EIA will also be evaluated. The objectives of this project are two-fold: l) Utilization of MoAB to TAG as reagents in pathological examination of cancers, 2) Commercialization of the TAG-EIA for Diagnosis and Management of Solid Cancers.