We show in this study that CRISPR-based screens have a significantly lower false-negative rate compared with RNAi-based screens, but have specific liabilities particularly in the interrogation of regions of genome amplification. Therefore, this study provides critical insights for applying CRISPR-based screens toward the systematic identification of new cancer targets. Cancer Discov; 6(8); 900-13. ©2016 AACR.See related commentary by Sheel and Xue, p. 824See related article by Aguirre et al., p. 914This article is highlighted in the In This Issue feature, p. 803.

<p>Supplementary Figure S1. Comparison of drop out phenotypes in MKN45, RKO, HT1080 highlighting selected pan-lethal genes. Supplementary Figure S2. The genes that scored as lethal by both RNAi and CRISPR were strongly enriched for known essential genes classes. Supplementary Figure S3. To identify likely off-target hits the lethality scores of non-expressed genes were examined, as they are expected not to be required for cell viability. Supplementary Figure S4. shRNAs directed towards CDK9 do not show robust protein depletion. Supplementary Figure S5. Additional methods measuring the proliferation effects of individual sgRNA/shRNAs to validate the impact that targeting selected genetic dependencies have on cell viability. Supplementary Figure S6. Correlation analysis displaying features that correlated most significantly with sgRNA potency. Supplementary Figure S7. Effect of relative position within a gene on sgRNA viability effects. Supplementary Figure S8. Non-scoring sgRNA in conserved Pfam domains have a reduced editing efficiency compared to guides with strong viability effects. Supplementary Figure S9. Multiple genomic cuts result in DNA damage induced G2/M cell cycle arrest. Supplementary Figure S10. Multiple genomic cuts lead to an increase in cell death. Supplementary Figure S11. Pie chart demonstrating that the overall contribution of copy number effects in determining essential genes in aneuploid lines is relatively minor.</p>

<p>Annotations for the sgRNA/shRNA libraries containing average Zscore and copy number information.</p>

<p>Correlation analysis matrix displaying features that correlate most strongly with sgRNA's having off target effects.</p>

<p>Locus-specific primer pairs.</p>