Human cancer cell lines indicated in the file names, with stably overexpressed Cas9 nuclease, were transfected with (C) control sgRNA or (P) TP53-specific sgRNA, (K) KRAS-specific sgRNA or (M) CMYC-specific sgRNA. Each experiment was done by transfection of sgRNA pair - control (C) or causing a NHEJ-mediated knock-out of the target genes (P, K or M). Samples for proteomics were collected 48h post sgRNA transfection without selection, in three biological replicates each (indicated with numbers 1-3). In cell lines with three activated oncogenes, three separate oncogene-targeting transfections were carried out.