Inhibition of Hsp90 results in downregulation of its client proteins [50], among them several oncogenic kinases like AKT, Raf-1, v-src [51–53] and also some important proteins in the biology of CLL cells like ZAP-70 [54], BCL2 and survivin [51]. Here, ZAP70 is linked to B-cell chronic lymphocytic leukemia.