As expected, we identified dependencies upon (1) FLT3 in the FLT3 wild-type overexpressing SEM cell line, (2) the checkpoint inhibitors ATR and CHK1 in the HAL-01 ALL cell line, and (3) ABL1 in TVA-1 cells, validating the specificity of our screens (Fig. 1B and Supplementary Fig. 1A). Here, CHEK1 is linked to acute lymphoblastic leukemia.