TP53 and osteosarcoma: Jie Xu et al. overexpressed wild-type and mutant p53 in the osteosarcoma SaOS-2 cell line and found that the overexpressed R273H (contact mutation) produced only similar chaperone levels to wild-type p53, but the overexpressed R175H (structure/aggregate mutation) induced a substantial upregulation of Hsp70 and Hsp90 [22].