CRISPR-Cas9 screen in dexamethasone-treated myeloma cell lines. (A) sgRNA waterfallplot of MM1S cells treated with 60 nM dexamethasone. (B) Significant hits from CRISPR-Cas9 screens for all cell lines. (C) Cell viability of KMS27- and MM1S-Cas9 cells expressing gene targeting (PCDHGB4, PCDHA5, and FAM46c) or control sgRNAs after treatment with DMSO or dexamethasone for 4 days. (D) Paraprotein course and clonal evolution of patient 1 (Pred, prednisolone; Pom, pomalidomide).