Pevonedistat (MLN4924) inhibits NAE activity more selectively than the closely related ubiquitin-activating enzyme (UAE, also known as UBA1) and SUMO-activating enzyme (SAE; a heterodimer of SAE1 and UBA2 subunits), in purified enzyme and cellular assays. MLN4924 exhibits potent cytotoxic activity against a variety of human tumor-derived cell lines. Here, UBA1 is linked to neoplasm.