CRISPR-Cas9 screens in melphalan-treated MM cell lines. (A) sgRNA library ranked by z-score for MM1S cells treated with 2 µM melphalan. (B) z-score for the 4 different sgRNAs for genes that were significantly enriched (red) or depleted (blue) in the CRISPR-Cas9 screen in ≥1 cell line. (C) MM1S-Cas9 cells lentivirally expressing sgRNAs against luciferase (Luc), FANCA-, or TP53 were analyzed for knockout efficiency by western blot. Data are representative of 2 biological replicates. (D) MM1S-Cas9 cells were infected with Luc control- or FANCA-specific sgRNAs and treated with DMSO, melphalan, or lenalidomide for 7 days. Dose-response curves show viability normalized to DMSO treatment assessed by CellTiter-Glo. Error bars represent standard error of the mean for each drug concentration. (E) Treatment, paraprotein course (purple graph), and fishplots showing the clonal evolution from diagnosis to relapse in patient 8. Arrows indicate collection of BM samples (Thal, thalidomide).