HGF and B-cell chronic lymphocytic leukemia: It was of further interest to observe that, while CLL cells and NLCs do not constitutively produce HGF, they start to release it when they are co-cultured together: a significant amount of HGF (range: 400–600 pg/mL) was in fact detected in media from co-cultures and we confirmed, by cytofluorimetric analysis, the presence of intracytoplasmic HGF in both CLL cells and NLCs [56].