Building on these studies, the Lamba group used the CRISPR knockout library “Brunello” in chronic myelogenous leukemia (CML) K562 cells combined with etoposide exposure and also identified the genetic ablation of ABCC1 to increase etoposide-dependent toxicity [132]. Here, ABCC1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.