Current screening tests for colon cancer based on gastrointestinal (GI) bleeding as detected by pseudoperoxidase activity in fecal matter have high false positive detection rates. The aim of this project is to develop a more specific test (i.e., one with lower false positives) for lower GI bleeding by using a monoclonal antibody which reacts specifically with human hemoglobin. We intend to make the test design similar to that of the product currently used in physicians' offices or sold over the counter. In phase I, a murine hybridoma cell line, for which Summa is currently negotiating an exclusive license, will be obtained and used for producing significant quantities of antibody. A prototype diagnostic product will be designed and tested using mockup fecal samples which contain varying amounts of blood, and/or hemoglobin from different animal species so that sensitivity and specificity can be quantitatively determined. Also, a design for a human trial will be developed. In phase II, clinical trials will be initiated by obtaining stool samples from patients with known sources of GI bleeding and from control subjects. Sensitivity and specificity for the detection of colorectal bleeding will be determined and compared to that measured using currently available tests. (5)