Lyn is the most important Src kinase in CLL, aberrantly localized in the cytosol, part of another cytosolic complex along with HS1-SHIP1-HSP90, constitutively phosphorylated on Tyr396, its inhibition/dephosphorylation triggering apoptosis [8,25]. The gene discussed is LYN; the disease is B-cell chronic lymphocytic leukemia.