Downregulation of USP7 by P5091 (a USP7 inhibitor) in MM cell lines, an MM xenograft model, and patient-derived tumor cells can create a potent and specific inhibitor that enhances degradation of HDM2, as well as upregulation of p53 and p21 expression, resulting in cell cytotoxicity [118]. This evidence concerns the gene USP7 and neoplasm.