We found consistent in vivo inhibitory effects of pevonedistat on the NEDDylation of cullins, and activation of p-ERK1/2 in the NALM6-Luc cells harvested from mice treated with pevonedistat ± SEL, and these findings were comparable to the in vitro data obtained with ALL cell lines and primary ALL cells [4]. Here, CACUL1 is linked to acute lymphoblastic leukemia.