PGF and diffuse large B-cell lymphoma: This conclusion was reached when geninstein, a broad tyrosine kinase blocker, inhibited the PlGF-mediated cleavage of Flt1 in SKI-DLBCL cells and was strengthened when a mutation in the activation loop of Flt1 that enhanced tyrosine phosphorylation also increased VEGF-mediated cleavage of Flt1 in porcine aortic endothelial cells.