For all identified essential genes except FAM22A, we observed a correlation between DNA copy number and transcript level across 947 human cancer cell lines from the CCLE23 (Supplementary Fig. 9), and data from pooled CRISPR/Cas920,38 and shRNA knockdown screens2,5,47 indicate that hemizygous deletion of HAUS6, RPS6, SMU1, NOL6, RPP30, MED4, INTS6, and ELAC2 increases the sensitivity to further knockdown of these genes (Supplementary Table 2). This evidence concerns the gene ELAC2 and cancer.