Next, to interrogate if CD79a, BCAP or PLCγ2 were indeed the targets of the HSP90 chaperon complex, HSP90 was immunoprecipitated from CLL cell lysates using an antibody to HSP90αβ (Santa Cruz), Protein G-agarose beads (Cell Signaling Technologies) alone or isotype control antibody (IgG2a; Cell Signaling). This evidence concerns the gene PLCG2 and B-cell chronic lymphocytic leukemia.