CRBN and leukemia: To determine if this difference in essentiality is reflected in differential resistance acquisition, we focused on two BET Bromodomain targeting PROTACs: dBET6 (CRBN-based) and ARV-771 (VHL-based) that have matched cellular potency, including in the near-haploid human leukemia cell line KBM7 (Extended Data Fig. 1A)26,27.