MDM2 and neoplasm: USP15 deubiquitinates the E3 ligase MDM2 in colon cancer [41] and malignant hematopoiesis [76], and E6AP in cervical cancer [77,78], which prevents their ubiquitin-dependent degradation, resulting in the concomitant downregulation of p53 and target gene expression, thereby enhancing tumor cell survival.