MCL1 targeting increases venetoclax sensitivity in MM cell lines with 1q gain. (A) CDK7 knockout cells show diminished expression levels of the antiapoptotic protein MCL1. (B) CDK7 knockout cells were treated with varying concentrations of venetoclax (0-12 μM) for 24 hours. Cell viability was assessed by CTG assay. SCR, scramble; sg_CDK71, single-guide RNA 1 (CRISPR); sg_CDK72, single-guide RNA 2 (CRISPR); WT, wild-type.