An experimental study on differential diagnosis of tumor from inflammation by using 125I labeled Pisum sativum agglutinin.

We have reported that Pisum sativum agglutinin (PSA), a plant lectin which recognizes mannosyl residues, accumulates markedly in Ehrlich solid tumor (EST) and suggested the possibility of applying PSA to tumor imaging radiopharmaceuticals. In the present work, an inflammation was induced by implantation of cotton thread in the left rear leg skeletal muscle of ddY mice and Ehrlich ascites tumor cells were inoculated into the right rear leg. 67Ga-citrate accumulated in the tumor tissue and the inflammatory lesion to almost equal extents. On the other hand, 125I-PSA preferentially accumulated in tumor tissues in mice bearing both tumor and inflammation. The results suggest that differential diagnosis of tumor from inflammation using radiolabeled PSA may be possible.