HSP90AA1 and cancer: Although it is well documented that downregulation of Hsp90 leads to degradation of mutant p53 in cancer (Brosh & Rotter, 2009; Taipale et al., 2010), Western blot analysis demonstrated that depletion of Hsp90β, but not Hsp90α, significantly enhanced the expression of p53 in myoblasts (Figure 1i).