To better understand HSP70 and HSF1 regulation, we studied their RAS-dependent activation pathway in CLL (as described in Figure 1A), pointing out how high levels of HSP70 could be the result of HSF1 hyperactivation due, at least in part, to both the activation of PI3K/AKT/mTOR signal pathway and the inhibition of the RAF/MEK/ERK pathway [10]. Here, HSF1 is linked to B-cell chronic lymphocytic leukemia.