Search for useful biomarkers of pre- or early malignant colonic tumors.

1. CEA, a well established marker for benign and malignant colonic tumors is widely used for tissue staining and body fluid measurement. Highly specific monoclonal antibodies are now available. It is likely that CEA gene(s) will be available soon. 2. Monoclonal antibodies to blood group precursor antigens, especially extended LeX and LeY are also available and are known to detect premalignant lesions. 3. The demonstration that LeY is expressed in purified CEA specimens suggests a complementary relationship between the two markers of possible clinical utility. 4. Systematic comparison of both families of marker is timely. 5. Experienced pathologists have classified and standardized the histology of adenomatous polyps and their premalignant counterparts. The use of serial sections of identical tissues will permit comparison of several candidate markers in the same lesion. Selection of lesions which contain benign, malignant, and invasive components in the same section will provide best control, minimizing the need for exhaustive studies. 6. Laminin staining gives useful indication of early invasion through the basement membrane. It will complement morphologic and marker evidence for early malignancy and invasion. 7. It is unnecessary to investigate all polyps. Focus should be on high risk patients with (1) large polyps, severe dysplasia and advanced villous change, (2) synchronous polyps and invasive cancer, and (3) familial and other multiple polyposis disorders. 8. A plethora of other candidate markers is available, only a few of which are mentioned.