The relationship between Hsp90, mutant forms of p53, and CHIP became clearer when Wang et al. showed mutant p53 proteins are selectively downregulated by CHIP in cancer cells treated with an Hsp90 inhibitor, gambogic acid [124], in a ubiquitin–proteasome-dependent manner [125] (summarized in Figure 3A). This evidence concerns the gene TP53 and cancer.