Development of an ELISA to detect early local relapse of colorectal cancer.

The Y haptenic blood group determinant is expressed on the cells of malignant gastrointestinal tumours and on the normal gastrointestinal epithelium of individuals who can secrete blood group antigens. an enzyme-linked immunosorbent assay incorporating the high affinity biotin-avidin interaction was developed to measure the serum levels of antigens bearing the Y hapten in patients with colorectal cancer. The specificity of the assays was between 88 and 93% and the sensitivity in detecting extensive disease was between 24 and 34%. However, up to 67% of patients with local or abdominal recurrent disease secreted antigens expressing the Y hapten, whereas only 30% of patients with overt hepatic metastases secreted a similar antigen. Recognition of antigens bearing the Y hapten may therefore be useful in detecting early local relapse of colorectal cancer when a second operation to excise the recurrence may be possible.