The role of a new fibronectin receptor p55 in liver metastasis by mouse lymphoma

The liver is a target organ for lymphoma and other types of tumor cells. Because there is no basement membrane beneath the sinusoidal endothelium, metastasis of lymphomas to the liver may involve interaction of fibronectin on hepatocytes with a fibronectin receptor on lymphoma cells, although no such fibronectin receptors have yet been demonstrated. Recently, I developed a new monoclonal antibody, LAD-4, that recognizes a novel FN receptor in the mouse lymphoma cell line RL-_??_1. LAD-4 partially, but significantly, inhibited both migration and formation of metastasis by lymphoma cells in the liver, as determined by an in-vivo migration assay using radioisotopes and by a metastasis assay involving histological examination. There was a functional difference between LAD-4 and the antibody specific for lymphocyte-function-associated antigen 1. The latter only inhibited metastasis formation by lymphoma cells in the liver without affecting migration.