STUB1 and cancer: The heat shock protein HSP90 chaperone machinery is highly activated in cancer versus normal tissues, rendering them resistant to proteotoxic stress by supporting proper folding – and preventing aggregation – of conformationally aberrant oncoproteins including mutp53.8, 9 Both classes of mutp53 (structural and DNA-contact) require HSP90 for protection from degradation by their E3 ubiquitin ligases Mdm2 and CHIP (Figure 1a).