Since FBXO38 activity is dependent on neddylation, Dibus et al, treated cells with MLN4924 and observed a slight decrease in PD-1 levels in HEK293, Jurkat, and HPB-ALL cells (Fig. 2d, Fig. 3a–d of Dibus et al, 2024). Here, PDCD1 is linked to acute lymphoblastic leukemia.