As demonstrated by IHC of lung, liver and pancreas sections with anti-Vav1, anti-CSF-1R and anti-CSF-1 Abs, while CSF-1R is expressed in cells within the B-cell lymphoma, the ligand is expressed in the epithelial tissue where transgenic Vav1 is found. This evidence concerns the gene VAV1 and B-cell non-Hodgkin lymphoma.