Tumor/serum ratios of alphafetoprotein and radioimmunolocalization of primary liver cancer.

Twenty six patients with primary liver cancer (PLC) were injected with 131I-labeled antibodies to alphafetoprotein (AFP). Each patient was tested by external photoscanning, 24 and 48 hours after injection. Positive imaging in the tumors was obtained in only 50 percent of patients. Serum AFP levels did not correlate with the radioimmunolocalization results. In 15 patients with PLC, concentrations of AFP in the tumors and sera were determined simultaneously. Although tumor AFP concentrations correlated significantly with serum AFP levels, tumor/serum AFP ratios differed greatly among tumors, indicating that there exists a dissociation between the production and the secretion of AFP. In 8 patients in whom the measurement of serum and tumor AFP concentrations and radioimmunolocalization were performed, tumor/serum AFP ratios correlated significantly with the results of radioimmunolocalization. This suggests that a high tumor/serum AFP ratio is important for the detection of PLC by radioimmunolocalization with antibodies to AFP.