ERBB2 and cancer: To derive candidate synthetic lethal genes in PSILC high scoring cell lines while accounting for the known vulnerabilities of ERBB2 amplified cancers, we compared DepMap’s aggregated CRISPR-Cas9 gene effect profiles [54] between (1) PSILC high vs. low group, and (2) PSILC highERBB2-WT vs. low group (Supplementary Tables 14 and 15, “Methods: CRISPR perturbation screens analysis”).