CDK8 and colorectal cancer: To better understand the selectivity of chemical probe compoundsand the roles of CDK8 and CDK19 in human colorectal cancer models,we employed a combination of our previously characterized CDK8/19tool compounds and CRISPR/Cas9-generated knockouts.−, , ,  The effects of these orthogonal perturbations wereevaluated using phospho-proteomics, promoter reporter assays, geneexpression profiling, growth assays, and solid tumor xenograft modelsin nude mice.