STUB1 and cancer: Both Hsp40 and CHIP interact with Hsp70, and Hsp70 cooperates with Hsp90 in stabilizing mutp53.11 Yet, Hsp70 was not implicated in mutp53 degradation by statins, although it should be noted that only the constitutively expressed Hsc70, but not the stress-induced cancer-relevant Hsp70, was analyzed.10 The Hsp40/DNAJ family of co-chaperones modulate the activity of Hsp70 chaperones by stimulating their basal ATPase activity and substrate affinity,8 whereas CHIP (carboxy-terminus of Hsp70-interacting protein) promotes degradation of Hsp70-bound misfolded proteins.